diff --git a/Generator/Program.cs b/Generator/Program.cs
index 4f04e2b..6353e14 100644
--- a/Generator/Program.cs
+++ b/Generator/Program.cs
@@ -39,6 +39,9 @@ string GetContent(bool isStruct, int i) {
     
     sb.Append(@$"using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {{
@@ -100,6 +103,19 @@ public void Switch({RangeJoined(", ", e => $"Action<T{e}> f{e}")})
             throw new InvalidOperationException();
         }}
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync({RangeJoined(", ", e => $"Func<T{e},Task> f{e}")})
+        {{
+            {RangeJoined(@"
+            ", j => @$"if (_index == {j} && f{j} != null)
+            {{
+                await f{j}(_value{j});
+                return;
+            }}")}
+            throw new InvalidOperationException();
+        }}
+#endif
+
         public TResult Match<TResult>({RangeJoined(", ", e => $"Func<T{e}, TResult> f{e}")})
         {{
             {RangeJoined(@"
@@ -110,6 +126,18 @@ public TResult Match<TResult>({RangeJoined(", ", e => $"Func<T{e}, TResult> f{e}
             throw new InvalidOperationException();
         }}
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>({RangeJoined(", ", e => $"Func<T{e}, Task<TResult>> f{e}")})
+        {{
+            {RangeJoined(@"
+            ", j => $@"if (_index == {j} && f{j} != null)
+            {{
+                return await f{j}(_value{j});
+            }}")}
+            throw new InvalidOperationException();
+        }}
+#endif
+
         {IfStruct(genericArgs.Joined(@"
         ", bindToType => $@"public static OneOf<{genericArgs.Joined(", ")}> From{bindToType}({bindToType} input) => input;"))}
 
@@ -134,7 +162,26 @@ public TResult Match<TResult>({RangeJoined(", ", e => $"Func<T{e}, TResult> f{e}
                         $"{k} => As{x},")}
                 _ => throw new InvalidOperationException()
             }};
-        }}";
+        }}
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<{resultArgsPrinted}>> Map{bindToType}Async<TResult>(Func<{bindToType}, Task<TResult>> mapFunc)
+        {{
+            if (mapFunc == null)
+            {{
+                throw new ArgumentNullException(nameof(mapFunc));
+            }}
+            return _index switch
+            {{
+                {genericArgs.Joined(@"
+                ", (x, k) =>
+                    x == bindToType ?
+                        $"{k} => await mapFunc(As{x})," :
+                        $"{k} => As{x},")}
+                _ => throw new InvalidOperationException()
+            }};
+        }}
+#endif";
         }))}
 ");
 
diff --git a/OneOf.Extended/OneOfBaseT10.generated.cs b/OneOf.Extended/OneOfBaseT10.generated.cs
index 3c61780..bc7c867 100644
--- a/OneOf.Extended/OneOfBaseT10.generated.cs
+++ b/OneOf.Extended/OneOfBaseT10.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -176,6 +179,68 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10)
         {
             if (_index == 0 && f0 != null)
@@ -225,6 +290,57 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT11.generated.cs b/OneOf.Extended/OneOfBaseT11.generated.cs
index cc72a59..ea6ccdb 100644
--- a/OneOf.Extended/OneOfBaseT11.generated.cs
+++ b/OneOf.Extended/OneOfBaseT11.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -189,6 +192,73 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11)
         {
             if (_index == 0 && f0 != null)
@@ -242,6 +312,61 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT12.generated.cs b/OneOf.Extended/OneOfBaseT12.generated.cs
index 7b9c66d..b3e4a5c 100644
--- a/OneOf.Extended/OneOfBaseT12.generated.cs
+++ b/OneOf.Extended/OneOfBaseT12.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -202,6 +205,78 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12)
         {
             if (_index == 0 && f0 != null)
@@ -259,6 +334,65 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT13.generated.cs b/OneOf.Extended/OneOfBaseT13.generated.cs
index ccf0cd7..e8f4b7a 100644
--- a/OneOf.Extended/OneOfBaseT13.generated.cs
+++ b/OneOf.Extended/OneOfBaseT13.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -215,6 +218,83 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13)
         {
             if (_index == 0 && f0 != null)
@@ -276,6 +356,69 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT14.generated.cs b/OneOf.Extended/OneOfBaseT14.generated.cs
index cade467..3b38b92 100644
--- a/OneOf.Extended/OneOfBaseT14.generated.cs
+++ b/OneOf.Extended/OneOfBaseT14.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -228,6 +231,88 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14)
         {
             if (_index == 0 && f0 != null)
@@ -293,6 +378,73 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT15.generated.cs b/OneOf.Extended/OneOfBaseT15.generated.cs
index 05132d2..9d737c5 100644
--- a/OneOf.Extended/OneOfBaseT15.generated.cs
+++ b/OneOf.Extended/OneOfBaseT15.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -241,6 +244,93 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15)
         {
             if (_index == 0 && f0 != null)
@@ -310,6 +400,77 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT16.generated.cs b/OneOf.Extended/OneOfBaseT16.generated.cs
index d59e70a..d05dbcd 100644
--- a/OneOf.Extended/OneOfBaseT16.generated.cs
+++ b/OneOf.Extended/OneOfBaseT16.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -254,6 +257,98 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16)
         {
             if (_index == 0 && f0 != null)
@@ -327,6 +422,81 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT17.generated.cs b/OneOf.Extended/OneOfBaseT17.generated.cs
index b50d501..9f69d54 100644
--- a/OneOf.Extended/OneOfBaseT17.generated.cs
+++ b/OneOf.Extended/OneOfBaseT17.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -267,6 +270,103 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17)
         {
             if (_index == 0 && f0 != null)
@@ -344,6 +444,85 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT18.generated.cs b/OneOf.Extended/OneOfBaseT18.generated.cs
index 9749b93..e4139df 100644
--- a/OneOf.Extended/OneOfBaseT18.generated.cs
+++ b/OneOf.Extended/OneOfBaseT18.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -280,6 +283,108 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18)
         {
             if (_index == 0 && f0 != null)
@@ -361,6 +466,89 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT19.generated.cs b/OneOf.Extended/OneOfBaseT19.generated.cs
index 76a2c60..2d3962a 100644
--- a/OneOf.Extended/OneOfBaseT19.generated.cs
+++ b/OneOf.Extended/OneOfBaseT19.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -293,6 +296,113 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19)
         {
             if (_index == 0 && f0 != null)
@@ -378,6 +488,93 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT20.generated.cs b/OneOf.Extended/OneOfBaseT20.generated.cs
index 7f69d8f..7eac361 100644
--- a/OneOf.Extended/OneOfBaseT20.generated.cs
+++ b/OneOf.Extended/OneOfBaseT20.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -306,6 +309,118 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20)
         {
             if (_index == 0 && f0 != null)
@@ -395,6 +510,97 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT21.generated.cs b/OneOf.Extended/OneOfBaseT21.generated.cs
index a6b02ee..02eb4b8 100644
--- a/OneOf.Extended/OneOfBaseT21.generated.cs
+++ b/OneOf.Extended/OneOfBaseT21.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -319,6 +322,123 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21)
         {
             if (_index == 0 && f0 != null)
@@ -412,6 +532,101 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT22.generated.cs b/OneOf.Extended/OneOfBaseT22.generated.cs
index daca4ef..fb9d05c 100644
--- a/OneOf.Extended/OneOfBaseT22.generated.cs
+++ b/OneOf.Extended/OneOfBaseT22.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -332,6 +335,128 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22)
         {
             if (_index == 0 && f0 != null)
@@ -429,6 +554,105 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT23.generated.cs b/OneOf.Extended/OneOfBaseT23.generated.cs
index 78a26b5..df3ee13 100644
--- a/OneOf.Extended/OneOfBaseT23.generated.cs
+++ b/OneOf.Extended/OneOfBaseT23.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -345,6 +348,133 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23)
         {
             if (_index == 0 && f0 != null)
@@ -446,6 +576,109 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT24.generated.cs b/OneOf.Extended/OneOfBaseT24.generated.cs
index c291a10..d9af976 100644
--- a/OneOf.Extended/OneOfBaseT24.generated.cs
+++ b/OneOf.Extended/OneOfBaseT24.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -358,6 +361,138 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24)
         {
             if (_index == 0 && f0 != null)
@@ -463,6 +598,113 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT25.generated.cs b/OneOf.Extended/OneOfBaseT25.generated.cs
index dc06dc9..3a47eb8 100644
--- a/OneOf.Extended/OneOfBaseT25.generated.cs
+++ b/OneOf.Extended/OneOfBaseT25.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -371,6 +374,143 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25)
         {
             if (_index == 0 && f0 != null)
@@ -480,6 +620,117 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT26.generated.cs b/OneOf.Extended/OneOfBaseT26.generated.cs
index edd010b..6086a24 100644
--- a/OneOf.Extended/OneOfBaseT26.generated.cs
+++ b/OneOf.Extended/OneOfBaseT26.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -384,6 +387,148 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25, Func<T26,Task> f26)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            if (_index == 26 && f26 != null)
+            {
+                await f26(_value26);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25, Func<T26, TResult> f26)
         {
             if (_index == 0 && f0 != null)
@@ -497,6 +642,121 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25, Func<T26, Task<TResult>> f26)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            if (_index == 26 && f26 != null)
+            {
+                return await f26(_value26);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT27.generated.cs b/OneOf.Extended/OneOfBaseT27.generated.cs
index ae54cde..7171b71 100644
--- a/OneOf.Extended/OneOfBaseT27.generated.cs
+++ b/OneOf.Extended/OneOfBaseT27.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -397,6 +400,153 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25, Func<T26,Task> f26, Func<T27,Task> f27)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            if (_index == 26 && f26 != null)
+            {
+                await f26(_value26);
+                return;
+            }
+            if (_index == 27 && f27 != null)
+            {
+                await f27(_value27);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25, Func<T26, TResult> f26, Func<T27, TResult> f27)
         {
             if (_index == 0 && f0 != null)
@@ -514,6 +664,125 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25, Func<T26, Task<TResult>> f26, Func<T27, Task<TResult>> f27)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            if (_index == 26 && f26 != null)
+            {
+                return await f26(_value26);
+            }
+            if (_index == 27 && f27 != null)
+            {
+                return await f27(_value27);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT28.generated.cs b/OneOf.Extended/OneOfBaseT28.generated.cs
index 611c63e..a3557f2 100644
--- a/OneOf.Extended/OneOfBaseT28.generated.cs
+++ b/OneOf.Extended/OneOfBaseT28.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -410,6 +413,158 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25, Func<T26,Task> f26, Func<T27,Task> f27, Func<T28,Task> f28)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            if (_index == 26 && f26 != null)
+            {
+                await f26(_value26);
+                return;
+            }
+            if (_index == 27 && f27 != null)
+            {
+                await f27(_value27);
+                return;
+            }
+            if (_index == 28 && f28 != null)
+            {
+                await f28(_value28);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25, Func<T26, TResult> f26, Func<T27, TResult> f27, Func<T28, TResult> f28)
         {
             if (_index == 0 && f0 != null)
@@ -531,6 +686,129 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25, Func<T26, Task<TResult>> f26, Func<T27, Task<TResult>> f27, Func<T28, Task<TResult>> f28)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            if (_index == 26 && f26 != null)
+            {
+                return await f26(_value26);
+            }
+            if (_index == 27 && f27 != null)
+            {
+                return await f27(_value27);
+            }
+            if (_index == 28 && f28 != null)
+            {
+                return await f28(_value28);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT29.generated.cs b/OneOf.Extended/OneOfBaseT29.generated.cs
index 8348e0d..480ef2e 100644
--- a/OneOf.Extended/OneOfBaseT29.generated.cs
+++ b/OneOf.Extended/OneOfBaseT29.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -423,6 +426,163 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25, Func<T26,Task> f26, Func<T27,Task> f27, Func<T28,Task> f28, Func<T29,Task> f29)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            if (_index == 26 && f26 != null)
+            {
+                await f26(_value26);
+                return;
+            }
+            if (_index == 27 && f27 != null)
+            {
+                await f27(_value27);
+                return;
+            }
+            if (_index == 28 && f28 != null)
+            {
+                await f28(_value28);
+                return;
+            }
+            if (_index == 29 && f29 != null)
+            {
+                await f29(_value29);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25, Func<T26, TResult> f26, Func<T27, TResult> f27, Func<T28, TResult> f28, Func<T29, TResult> f29)
         {
             if (_index == 0 && f0 != null)
@@ -548,6 +708,133 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25, Func<T26, Task<TResult>> f26, Func<T27, Task<TResult>> f27, Func<T28, Task<TResult>> f28, Func<T29, Task<TResult>> f29)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            if (_index == 26 && f26 != null)
+            {
+                return await f26(_value26);
+            }
+            if (_index == 27 && f27 != null)
+            {
+                return await f27(_value27);
+            }
+            if (_index == 28 && f28 != null)
+            {
+                return await f28(_value28);
+            }
+            if (_index == 29 && f29 != null)
+            {
+                return await f29(_value29);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT30.generated.cs b/OneOf.Extended/OneOfBaseT30.generated.cs
index 25229bd..f12ff06 100644
--- a/OneOf.Extended/OneOfBaseT30.generated.cs
+++ b/OneOf.Extended/OneOfBaseT30.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -436,6 +439,168 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25, Func<T26,Task> f26, Func<T27,Task> f27, Func<T28,Task> f28, Func<T29,Task> f29, Func<T30,Task> f30)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            if (_index == 26 && f26 != null)
+            {
+                await f26(_value26);
+                return;
+            }
+            if (_index == 27 && f27 != null)
+            {
+                await f27(_value27);
+                return;
+            }
+            if (_index == 28 && f28 != null)
+            {
+                await f28(_value28);
+                return;
+            }
+            if (_index == 29 && f29 != null)
+            {
+                await f29(_value29);
+                return;
+            }
+            if (_index == 30 && f30 != null)
+            {
+                await f30(_value30);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25, Func<T26, TResult> f26, Func<T27, TResult> f27, Func<T28, TResult> f28, Func<T29, TResult> f29, Func<T30, TResult> f30)
         {
             if (_index == 0 && f0 != null)
@@ -565,6 +730,137 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25, Func<T26, Task<TResult>> f26, Func<T27, Task<TResult>> f27, Func<T28, Task<TResult>> f28, Func<T29, Task<TResult>> f29, Func<T30, Task<TResult>> f30)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            if (_index == 26 && f26 != null)
+            {
+                return await f26(_value26);
+            }
+            if (_index == 27 && f27 != null)
+            {
+                return await f27(_value27);
+            }
+            if (_index == 28 && f28 != null)
+            {
+                return await f28(_value28);
+            }
+            if (_index == 29 && f29 != null)
+            {
+                return await f29(_value29);
+            }
+            if (_index == 30 && f30 != null)
+            {
+                return await f30(_value30);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT31.generated.cs b/OneOf.Extended/OneOfBaseT31.generated.cs
index 9a1fa4d..1be0ed8 100644
--- a/OneOf.Extended/OneOfBaseT31.generated.cs
+++ b/OneOf.Extended/OneOfBaseT31.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -449,6 +452,173 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25, Func<T26,Task> f26, Func<T27,Task> f27, Func<T28,Task> f28, Func<T29,Task> f29, Func<T30,Task> f30, Func<T31,Task> f31)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            if (_index == 26 && f26 != null)
+            {
+                await f26(_value26);
+                return;
+            }
+            if (_index == 27 && f27 != null)
+            {
+                await f27(_value27);
+                return;
+            }
+            if (_index == 28 && f28 != null)
+            {
+                await f28(_value28);
+                return;
+            }
+            if (_index == 29 && f29 != null)
+            {
+                await f29(_value29);
+                return;
+            }
+            if (_index == 30 && f30 != null)
+            {
+                await f30(_value30);
+                return;
+            }
+            if (_index == 31 && f31 != null)
+            {
+                await f31(_value31);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25, Func<T26, TResult> f26, Func<T27, TResult> f27, Func<T28, TResult> f28, Func<T29, TResult> f29, Func<T30, TResult> f30, Func<T31, TResult> f31)
         {
             if (_index == 0 && f0 != null)
@@ -582,6 +752,141 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25, Func<T26, Task<TResult>> f26, Func<T27, Task<TResult>> f27, Func<T28, Task<TResult>> f28, Func<T29, Task<TResult>> f29, Func<T30, Task<TResult>> f30, Func<T31, Task<TResult>> f31)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            if (_index == 26 && f26 != null)
+            {
+                return await f26(_value26);
+            }
+            if (_index == 27 && f27 != null)
+            {
+                return await f27(_value27);
+            }
+            if (_index == 28 && f28 != null)
+            {
+                return await f28(_value28);
+            }
+            if (_index == 29 && f29 != null)
+            {
+                return await f29(_value29);
+            }
+            if (_index == 30 && f30 != null)
+            {
+                return await f30(_value30);
+            }
+            if (_index == 31 && f31 != null)
+            {
+                return await f31(_value31);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfBaseT9.generated.cs b/OneOf.Extended/OneOfBaseT9.generated.cs
index 9510257..ff66bb2 100644
--- a/OneOf.Extended/OneOfBaseT9.generated.cs
+++ b/OneOf.Extended/OneOfBaseT9.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -163,6 +166,63 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9)
         {
             if (_index == 0 && f0 != null)
@@ -208,6 +268,53 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf.Extended/OneOfT10.generated.cs b/OneOf.Extended/OneOfT10.generated.cs
index 1297e00..591f1ac 100644
--- a/OneOf.Extended/OneOfT10.generated.cs
+++ b/OneOf.Extended/OneOfT10.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -182,6 +185,68 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10)
         {
             if (_index == 0 && f0 != null)
@@ -231,6 +296,57 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10> FromT2(T2 input) => input;
@@ -266,6 +382,31 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10> MapT0<TResult>(Fu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -289,6 +430,31 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10> MapT1<TResult>(Fu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -312,6 +478,31 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10> MapT2<TResult>(Fu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
@@ -335,6 +526,31 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10> MapT3<TResult>(Fu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
@@ -358,6 +574,31 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10> MapT4<TResult>(Fu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
@@ -381,6 +622,31 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10> MapT5<TResult>(Fu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
@@ -404,6 +670,31 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10> MapT6<TResult>(Fu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
@@ -427,6 +718,31 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10> MapT7<TResult>(Fu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10> MapT8<TResult>(Func<T8, TResult> mapFunc)
         {
@@ -450,6 +766,31 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10> MapT8<TResult>(Fu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10> MapT9<TResult>(Func<T9, TResult> mapFunc)
         {
@@ -473,6 +814,31 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10> MapT9<TResult>(Fu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult> MapT10<TResult>(Func<T10, TResult> mapFunc)
         {
@@ -497,6 +863,31 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult> MapT10<TResult>(Fu
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT11.generated.cs b/OneOf.Extended/OneOfT11.generated.cs
index 4b97d9f..6b08c95 100644
--- a/OneOf.Extended/OneOfT11.generated.cs
+++ b/OneOf.Extended/OneOfT11.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -196,6 +199,73 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11)
         {
             if (_index == 0 && f0 != null)
@@ -249,6 +319,61 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> FromT2(T2 input) => input;
@@ -286,6 +411,32 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> MapT0<TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -310,6 +461,32 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> MapT1<TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -334,6 +511,32 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11> MapT2<TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
@@ -358,6 +561,32 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11> MapT3<TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
@@ -382,6 +611,32 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11> MapT4<TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
@@ -406,6 +661,32 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11> MapT5<TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
@@ -430,6 +711,32 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11> MapT6<TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
@@ -454,6 +761,32 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11> MapT7<TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11> MapT8<TResult>(Func<T8, TResult> mapFunc)
         {
@@ -478,6 +811,32 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11> MapT8<TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11> MapT9<TResult>(Func<T9, TResult> mapFunc)
         {
@@ -502,6 +861,32 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11> MapT9<TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11> MapT10<TResult>(Func<T10, TResult> mapFunc)
         {
@@ -526,6 +911,32 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11> MapT10<TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult> MapT11<TResult>(Func<T11, TResult> mapFunc)
         {
@@ -551,6 +962,32 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult> MapT11<TResul
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT12.generated.cs b/OneOf.Extended/OneOfT12.generated.cs
index 0801a8b..0604307 100644
--- a/OneOf.Extended/OneOfT12.generated.cs
+++ b/OneOf.Extended/OneOfT12.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -210,6 +213,78 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12)
         {
             if (_index == 0 && f0 != null)
@@ -267,6 +342,65 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12> FromT2(T2 input) => input;
@@ -306,6 +440,33 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12> MapT0<T
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -331,6 +492,33 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12> MapT1<T
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -356,6 +544,33 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12> MapT2<T
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
@@ -381,6 +596,33 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12> MapT3<T
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
@@ -406,6 +648,33 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12> MapT4<T
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
@@ -431,6 +700,33 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12> MapT5<T
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
@@ -456,6 +752,33 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12> MapT6<T
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
@@ -481,6 +804,33 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12> MapT7<T
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12> MapT8<TResult>(Func<T8, TResult> mapFunc)
         {
@@ -506,6 +856,33 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12> MapT8<T
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12> MapT9<TResult>(Func<T9, TResult> mapFunc)
         {
@@ -531,6 +908,33 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12> MapT9<T
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12> MapT10<TResult>(Func<T10, TResult> mapFunc)
         {
@@ -556,6 +960,33 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12> MapT10<T
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12> MapT11<TResult>(Func<T11, TResult> mapFunc)
         {
@@ -581,6 +1012,33 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12> MapT11<T
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult> MapT12<TResult>(Func<T12, TResult> mapFunc)
         {
@@ -607,6 +1065,33 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult> MapT12<T
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT13.generated.cs b/OneOf.Extended/OneOfT13.generated.cs
index c5d1ac5..eaad861 100644
--- a/OneOf.Extended/OneOfT13.generated.cs
+++ b/OneOf.Extended/OneOfT13.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -224,6 +227,83 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13)
         {
             if (_index == 0 && f0 != null)
@@ -285,6 +365,69 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13> FromT2(T2 input) => input;
@@ -326,6 +469,34 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13> Ma
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -352,6 +523,34 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13> Ma
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -378,6 +577,34 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13> Ma
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
@@ -404,6 +631,34 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13> Ma
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
@@ -430,6 +685,34 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13> Ma
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
@@ -456,6 +739,34 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13> Ma
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
@@ -482,6 +793,34 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13> Ma
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
@@ -508,6 +847,34 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13> Ma
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13> MapT8<TResult>(Func<T8, TResult> mapFunc)
         {
@@ -534,6 +901,34 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13> Ma
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13> MapT9<TResult>(Func<T9, TResult> mapFunc)
         {
@@ -560,6 +955,34 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13> Ma
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13> MapT10<TResult>(Func<T10, TResult> mapFunc)
         {
@@ -586,6 +1009,34 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13> Map
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13> MapT11<TResult>(Func<T11, TResult> mapFunc)
         {
@@ -612,6 +1063,34 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13> Map
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13> MapT12<TResult>(Func<T12, TResult> mapFunc)
         {
@@ -638,6 +1117,34 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13> Map
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                13 => AsT13,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult> MapT13<TResult>(Func<T13, TResult> mapFunc)
         {
@@ -665,6 +1172,34 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult> Map
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => await mapFunc(AsT13),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT14.generated.cs b/OneOf.Extended/OneOfT14.generated.cs
index e7e9578..7c68c2e 100644
--- a/OneOf.Extended/OneOfT14.generated.cs
+++ b/OneOf.Extended/OneOfT14.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -238,6 +241,88 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14)
         {
             if (_index == 0 && f0 != null)
@@ -303,6 +388,73 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14> FromT2(T2 input) => input;
@@ -346,6 +498,35 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -373,6 +554,35 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -400,6 +610,35 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
@@ -427,6 +666,35 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
@@ -454,6 +722,35 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
@@ -481,6 +778,35 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
@@ -508,6 +834,35 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
@@ -535,6 +890,35 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14> MapT8<TResult>(Func<T8, TResult> mapFunc)
         {
@@ -562,6 +946,35 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14> MapT9<TResult>(Func<T9, TResult> mapFunc)
         {
@@ -589,6 +1002,35 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14> MapT10<TResult>(Func<T10, TResult> mapFunc)
         {
@@ -616,6 +1058,35 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14> MapT11<TResult>(Func<T11, TResult> mapFunc)
         {
@@ -643,6 +1114,35 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14> MapT12<TResult>(Func<T12, TResult> mapFunc)
         {
@@ -670,6 +1170,35 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14> MapT13<TResult>(Func<T13, TResult> mapFunc)
         {
@@ -697,6 +1226,35 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => await mapFunc(AsT13),
+                14 => AsT14,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult> MapT14<TResult>(Func<T14, TResult> mapFunc)
         {
@@ -725,6 +1283,35 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => await mapFunc(AsT14),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT15.generated.cs b/OneOf.Extended/OneOfT15.generated.cs
index 8c3b91d..919a478 100644
--- a/OneOf.Extended/OneOfT15.generated.cs
+++ b/OneOf.Extended/OneOfT15.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -252,6 +255,93 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15)
         {
             if (_index == 0 && f0 != null)
@@ -321,6 +411,77 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15> FromT2(T2 input) => input;
@@ -366,6 +527,36 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -394,6 +585,36 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -422,8 +643,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15> MapT3<TResult>(Func<T3, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -433,8 +655,8 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => AsT2,
-                3 => mapFunc(AsT3),
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -450,8 +672,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -462,8 +685,8 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => AsT3,
-                4 => mapFunc(AsT4),
+                3 => mapFunc(AsT3),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -478,8 +701,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15> MapT5<TResult>(Func<T5, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -490,9 +714,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => AsT3,
+                3 => await mapFunc(AsT3),
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -506,8 +730,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -519,9 +744,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => AsT4,
+                4 => mapFunc(AsT4),
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -534,8 +759,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15> MapT7<TResult>(Func<T7, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -547,10 +773,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => AsT4,
+                4 => await mapFunc(AsT4),
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -562,8 +788,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -576,10 +803,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => AsT5,
+                5 => mapFunc(AsT5),
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -590,8 +817,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15> MapT9<TResult>(Func<T9, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -604,11 +832,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => AsT5,
+                5 => await mapFunc(AsT5),
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -618,8 +846,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -633,11 +862,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => AsT6,
+                6 => mapFunc(AsT6),
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -646,8 +875,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15> MapT11<TResult>(Func<T11, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -661,12 +891,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => AsT6,
+                6 => await mapFunc(AsT6),
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -674,8 +904,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -690,20 +921,21 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => AsT7,
+                7 => mapFunc(AsT7),
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15> MapT13<TResult>(Func<T13, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -718,20 +950,21 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => AsT7,
+                7 => await mapFunc(AsT7),
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15> MapT8<TResult>(Func<T8, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -747,19 +980,20 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => AsT8,
+                8 => mapFunc(AsT8),
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult> MapT15<TResult>(Func<T15, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -775,17 +1009,424 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => AsT8,
+                8 => await mapFunc(AsT8),
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => await mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => mapFunc(AsT14),
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => await mapFunc(AsT14),
+                15 => AsT15,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => mapFunc(AsT15),
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => await mapFunc(AsT15),
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
 
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15> remainder)
 		{
diff --git a/OneOf.Extended/OneOfT16.generated.cs b/OneOf.Extended/OneOfT16.generated.cs
index 51f8dc6..504dc59 100644
--- a/OneOf.Extended/OneOfT16.generated.cs
+++ b/OneOf.Extended/OneOfT16.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -266,6 +269,98 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16)
         {
             if (_index == 0 && f0 != null)
@@ -339,6 +434,81 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> FromT2(T2 input) => input;
@@ -386,6 +556,37 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -415,8 +616,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> MapT2<TResult>(Func<T2, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -425,8 +627,8 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => AsT1,
-                2 => mapFunc(AsT2),
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -444,8 +646,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -455,8 +658,8 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => AsT2,
-                3 => mapFunc(AsT3),
+                2 => mapFunc(AsT2),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -473,8 +676,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> MapT4<TResult>(Func<T4, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -484,9 +688,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => AsT2,
+                2 => await mapFunc(AsT2),
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -502,8 +706,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -514,9 +719,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => AsT3,
+                3 => mapFunc(AsT3),
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -531,8 +736,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> MapT6<TResult>(Func<T6, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -543,10 +749,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => AsT3,
+                3 => await mapFunc(AsT3),
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -560,8 +766,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -573,10 +780,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => AsT4,
+                4 => mapFunc(AsT4),
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -589,8 +796,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16> MapT8<TResult>(Func<T8, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -602,11 +810,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => AsT4,
+                4 => await mapFunc(AsT4),
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -618,8 +826,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -632,11 +841,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => AsT5,
+                5 => mapFunc(AsT5),
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -647,8 +856,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16> MapT10<TResult>(Func<T10, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -661,12 +871,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => AsT5,
+                5 => await mapFunc(AsT5),
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -676,8 +886,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -691,12 +902,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => AsT6,
+                6 => mapFunc(AsT6),
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -705,8 +916,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16> MapT12<TResult>(Func<T12, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -720,13 +932,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => AsT6,
+                6 => await mapFunc(AsT6),
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -734,8 +946,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -750,21 +963,22 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => AsT7,
+                7 => mapFunc(AsT7),
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16> MapT14<TResult>(Func<T14, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -779,21 +993,22 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => AsT7,
+                7 => await mapFunc(AsT7),
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16> MapT8<TResult>(Func<T8, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -809,20 +1024,21 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => AsT8,
+                8 => mapFunc(AsT8),
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult> MapT16<TResult>(Func<T16, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -838,7 +1054,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => AsT8,
+                8 => await mapFunc(AsT8),
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -846,10 +1062,491 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => await mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => mapFunc(AsT14),
+                15 => AsT15,
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => await mapFunc(AsT14),
+                15 => AsT15,
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => mapFunc(AsT15),
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => await mapFunc(AsT15),
+                16 => AsT16,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => mapFunc(AsT16),
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => await mapFunc(AsT16),
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
 
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> remainder)
 		{
diff --git a/OneOf.Extended/OneOfT17.generated.cs b/OneOf.Extended/OneOfT17.generated.cs
index eefe75b..03456e1 100644
--- a/OneOf.Extended/OneOfT17.generated.cs
+++ b/OneOf.Extended/OneOfT17.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -280,6 +283,103 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17)
         {
             if (_index == 0 && f0 != null)
@@ -357,6 +457,85 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> FromT2(T2 input) => input;
@@ -406,6 +585,38 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -436,8 +647,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT2<TResult>(Func<T2, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -446,8 +658,8 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => AsT1,
-                2 => mapFunc(AsT2),
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -466,8 +678,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -477,8 +690,8 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => AsT2,
-                3 => mapFunc(AsT3),
+                2 => mapFunc(AsT2),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -496,8 +709,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT4<TResult>(Func<T4, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -507,9 +721,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => AsT2,
+                2 => await mapFunc(AsT2),
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -526,8 +740,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -538,9 +753,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => AsT3,
+                3 => mapFunc(AsT3),
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -556,8 +771,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT6<TResult>(Func<T6, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -568,10 +784,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => AsT3,
+                3 => await mapFunc(AsT3),
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -586,8 +802,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -599,10 +816,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => AsT4,
+                4 => mapFunc(AsT4),
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -616,8 +833,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT8<TResult>(Func<T8, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -629,11 +847,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => AsT4,
+                4 => await mapFunc(AsT4),
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -646,8 +864,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -660,11 +879,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => AsT5,
+                5 => mapFunc(AsT5),
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -676,8 +895,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17> MapT10<TResult>(Func<T10, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -690,12 +910,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => AsT5,
+                5 => await mapFunc(AsT5),
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -706,8 +926,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -721,12 +942,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => AsT6,
+                6 => mapFunc(AsT6),
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -736,8 +957,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17> MapT12<TResult>(Func<T12, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -751,13 +973,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => AsT6,
+                6 => await mapFunc(AsT6),
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -766,8 +988,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -782,13 +1005,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => AsT7,
+                7 => mapFunc(AsT7),
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -796,8 +1019,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17> MapT14<TResult>(Func<T14, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -812,22 +1036,23 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => AsT7,
+                7 => await mapFunc(AsT7),
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17> MapT8<TResult>(Func<T8, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -843,21 +1068,22 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => AsT8,
+                8 => mapFunc(AsT8),
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17> MapT16<TResult>(Func<T16, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -873,7 +1099,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => AsT8,
+                8 => await mapFunc(AsT8),
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -881,13 +1107,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
                 17 => AsT17,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult> MapT17<TResult>(Func<T17, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17> MapT9<TResult>(Func<T9, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -904,7 +1131,503 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => AsT9,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => await mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => mapFunc(AsT14),
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => await mapFunc(AsT14),
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => mapFunc(AsT15),
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => await mapFunc(AsT15),
+                16 => AsT16,
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => mapFunc(AsT16),
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => await mapFunc(AsT16),
+                17 => AsT17,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult> MapT17<TResult>(Func<T17, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -917,6 +1640,38 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => await mapFunc(AsT17),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT18.generated.cs b/OneOf.Extended/OneOfT18.generated.cs
index ba17036..abd5ef9 100644
--- a/OneOf.Extended/OneOfT18.generated.cs
+++ b/OneOf.Extended/OneOfT18.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -294,6 +297,108 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18)
         {
             if (_index == 0 && f0 != null)
@@ -375,6 +480,89 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> FromT2(T2 input) => input;
@@ -426,8 +614,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT1<TResult>(Func<T1, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -435,8 +624,8 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => AsT0,
-                1 => mapFunc(AsT1),
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -457,8 +646,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -467,8 +657,8 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => AsT1,
-                2 => mapFunc(AsT2),
+                1 => mapFunc(AsT1),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -488,8 +678,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT3<TResult>(Func<T3, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -498,9 +689,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => AsT1,
+                1 => await mapFunc(AsT1),
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -519,8 +710,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -530,9 +722,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => AsT2,
+                2 => mapFunc(AsT2),
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -550,8 +742,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT5<TResult>(Func<T5, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -561,10 +754,10 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => AsT2,
+                2 => await mapFunc(AsT2),
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -581,8 +774,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -593,10 +787,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => AsT3,
+                3 => mapFunc(AsT3),
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -612,8 +806,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT7<TResult>(Func<T7, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -624,11 +819,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => AsT3,
+                3 => await mapFunc(AsT3),
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -643,8 +838,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -656,11 +852,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => AsT4,
+                4 => mapFunc(AsT4),
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -674,8 +870,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT9<TResult>(Func<T9, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -687,12 +884,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => AsT4,
+                4 => await mapFunc(AsT4),
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -705,8 +902,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -719,12 +917,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => AsT5,
+                5 => mapFunc(AsT5),
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -736,8 +934,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18> MapT11<TResult>(Func<T11, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -750,13 +949,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => AsT5,
+                5 => await mapFunc(AsT5),
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -767,8 +966,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -782,13 +982,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => AsT6,
+                6 => mapFunc(AsT6),
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -798,8 +998,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18> MapT13<TResult>(Func<T13, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -813,14 +1014,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => AsT6,
+                6 => await mapFunc(AsT6),
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -829,8 +1030,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -845,14 +1047,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => AsT7,
+                7 => mapFunc(AsT7),
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -860,8 +1062,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18> MapT15<TResult>(Func<T15, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -876,7 +1079,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => AsT7,
+                7 => await mapFunc(AsT7),
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -884,15 +1087,16 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT8<TResult>(Func<T8, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -908,7 +1112,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => AsT8,
+                8 => mapFunc(AsT8),
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -916,14 +1120,15 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18> MapT17<TResult>(Func<T17, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -939,7 +1144,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => AsT8,
+                8 => await mapFunc(AsT8),
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -948,13 +1153,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
+                17 => AsT17,
                 18 => AsT18,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult> MapT18<TResult>(Func<T18, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18> MapT9<TResult>(Func<T9, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -971,7 +1177,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => AsT9,
+                9 => mapFunc(AsT9),
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -980,10 +1186,619 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => mapFunc(AsT18),
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => await mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => mapFunc(AsT14),
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => await mapFunc(AsT14),
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => mapFunc(AsT15),
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => await mapFunc(AsT15),
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => mapFunc(AsT16),
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => await mapFunc(AsT16),
+                17 => AsT17,
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18> MapT17<TResult>(Func<T17, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => mapFunc(AsT17),
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => await mapFunc(AsT17),
+                18 => AsT18,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult> MapT18<TResult>(Func<T18, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => mapFunc(AsT18),
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => await mapFunc(AsT18),
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
 
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18> remainder)
 		{
diff --git a/OneOf.Extended/OneOfT19.generated.cs b/OneOf.Extended/OneOfT19.generated.cs
index 3541ffe..bfd6772 100644
--- a/OneOf.Extended/OneOfT19.generated.cs
+++ b/OneOf.Extended/OneOfT19.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -308,6 +311,113 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19)
         {
             if (_index == 0 && f0 != null)
@@ -393,6 +503,93 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> FromT2(T2 input) => input;
@@ -446,8 +643,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT1<TResult>(Func<T1, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -455,8 +653,8 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => AsT0,
-                1 => mapFunc(AsT1),
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -478,8 +676,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -488,8 +687,8 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => AsT1,
-                2 => mapFunc(AsT2),
+                1 => mapFunc(AsT1),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -510,8 +709,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT3<TResult>(Func<T3, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -520,9 +720,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => AsT1,
+                1 => await mapFunc(AsT1),
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -542,8 +742,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -553,9 +754,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => AsT2,
+                2 => mapFunc(AsT2),
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -574,8 +775,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT5<TResult>(Func<T5, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -585,10 +787,10 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => AsT2,
+                2 => await mapFunc(AsT2),
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -606,8 +808,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -618,10 +821,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => AsT3,
+                3 => mapFunc(AsT3),
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -638,8 +841,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT7<TResult>(Func<T7, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -650,11 +854,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => AsT3,
+                3 => await mapFunc(AsT3),
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -670,8 +874,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -683,11 +888,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => AsT4,
+                4 => mapFunc(AsT4),
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -702,8 +907,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT9<TResult>(Func<T9, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -715,12 +921,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => AsT4,
+                4 => await mapFunc(AsT4),
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -734,8 +940,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -748,12 +955,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => AsT5,
+                5 => mapFunc(AsT5),
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -766,8 +973,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19> MapT11<TResult>(Func<T11, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -780,13 +988,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => AsT5,
+                5 => await mapFunc(AsT5),
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -798,8 +1006,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -813,13 +1022,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => AsT6,
+                6 => mapFunc(AsT6),
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -830,8 +1039,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19> MapT13<TResult>(Func<T13, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -845,14 +1055,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => AsT6,
+                6 => await mapFunc(AsT6),
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -862,8 +1072,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -878,14 +1089,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => AsT7,
+                7 => mapFunc(AsT7),
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -894,8 +1105,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19> MapT15<TResult>(Func<T15, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -910,7 +1122,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => AsT7,
+                7 => await mapFunc(AsT7),
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -918,7 +1130,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -926,8 +1138,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT8<TResult>(Func<T8, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -943,7 +1156,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => AsT8,
+                8 => mapFunc(AsT8),
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -951,15 +1164,16 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19> MapT17<TResult>(Func<T17, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -975,7 +1189,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => AsT8,
+                8 => await mapFunc(AsT8),
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -984,14 +1198,15 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
+                17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19> MapT18<TResult>(Func<T18, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT9<TResult>(Func<T9, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1008,7 +1223,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => AsT9,
+                9 => mapFunc(AsT9),
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -1017,11 +1232,639 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => mapFunc(AsT18),
+                18 => AsT18,
                 19 => AsT19,
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => await mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => mapFunc(AsT14),
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => await mapFunc(AsT14),
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => mapFunc(AsT15),
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => await mapFunc(AsT15),
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => mapFunc(AsT16),
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => await mapFunc(AsT16),
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19> MapT17<TResult>(Func<T17, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => mapFunc(AsT17),
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => await mapFunc(AsT17),
+                18 => AsT18,
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19> MapT18<TResult>(Func<T18, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => mapFunc(AsT18),
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => await mapFunc(AsT18),
+                19 => AsT19,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult> MapT19<TResult>(Func<T19, TResult> mapFunc)
         {
@@ -1055,6 +1898,40 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult>> MapT19Async<TResult>(Func<T19, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => await mapFunc(AsT19),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT20.generated.cs b/OneOf.Extended/OneOfT20.generated.cs
index c03bd8b..59b3341 100644
--- a/OneOf.Extended/OneOfT20.generated.cs
+++ b/OneOf.Extended/OneOfT20.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -322,6 +325,118 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20)
         {
             if (_index == 0 && f0 != null)
@@ -411,6 +526,97 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> FromT2(T2 input) => input;
@@ -466,8 +672,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT1<TResult>(Func<T1, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -475,8 +682,8 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => AsT0,
-                1 => mapFunc(AsT1),
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -499,8 +706,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -509,8 +717,8 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => AsT1,
-                2 => mapFunc(AsT2),
+                1 => mapFunc(AsT1),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -532,8 +740,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT3<TResult>(Func<T3, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -542,9 +751,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => AsT1,
+                1 => await mapFunc(AsT1),
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -565,8 +774,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -576,9 +786,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => AsT2,
+                2 => mapFunc(AsT2),
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -598,8 +808,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT5<TResult>(Func<T5, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -609,10 +820,10 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => AsT2,
+                2 => await mapFunc(AsT2),
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -631,8 +842,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -643,10 +855,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => AsT3,
+                3 => mapFunc(AsT3),
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -664,8 +876,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT7<TResult>(Func<T7, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -676,11 +889,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => AsT3,
+                3 => await mapFunc(AsT3),
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -697,8 +910,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -710,11 +924,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => AsT4,
+                4 => mapFunc(AsT4),
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -730,8 +944,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT9<TResult>(Func<T9, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -743,12 +958,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => AsT4,
+                4 => await mapFunc(AsT4),
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -763,8 +978,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -777,12 +993,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => AsT5,
+                5 => mapFunc(AsT5),
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -796,8 +1012,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT11<TResult>(Func<T11, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -810,13 +1027,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => AsT5,
+                5 => await mapFunc(AsT5),
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -829,8 +1046,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -844,13 +1062,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => AsT6,
+                6 => mapFunc(AsT6),
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -862,8 +1080,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20> MapT13<TResult>(Func<T13, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -877,14 +1096,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => AsT6,
+                6 => await mapFunc(AsT6),
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -895,8 +1114,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -911,14 +1131,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => AsT7,
+                7 => mapFunc(AsT7),
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -928,8 +1148,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20> MapT15<TResult>(Func<T15, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -944,7 +1165,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => AsT7,
+                7 => await mapFunc(AsT7),
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -952,7 +1173,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -961,8 +1182,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT8<TResult>(Func<T8, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -978,7 +1200,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => AsT8,
+                8 => mapFunc(AsT8),
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -986,7 +1208,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -994,8 +1216,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20> MapT17<TResult>(Func<T17, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1011,7 +1234,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => AsT8,
+                8 => await mapFunc(AsT8),
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -1020,13 +1243,626 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => await mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => mapFunc(AsT14),
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => await mapFunc(AsT14),
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => mapFunc(AsT15),
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => await mapFunc(AsT15),
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => mapFunc(AsT16),
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => await mapFunc(AsT16),
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20> MapT17<TResult>(Func<T17, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => mapFunc(AsT17),
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => await mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20> MapT18<TResult>(Func<T18, TResult> mapFunc)
         {
@@ -1060,6 +1896,41 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => await mapFunc(AsT18),
+                19 => AsT19,
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20> MapT19<TResult>(Func<T19, TResult> mapFunc)
         {
@@ -1093,6 +1964,41 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20>> MapT19Async<TResult>(Func<T19, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => await mapFunc(AsT19),
+                20 => AsT20,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult> MapT20<TResult>(Func<T20, TResult> mapFunc)
         {
@@ -1127,6 +2033,41 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult>> MapT20Async<TResult>(Func<T20, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => await mapFunc(AsT20),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT21.generated.cs b/OneOf.Extended/OneOfT21.generated.cs
index 1d89b7b..df179ee 100644
--- a/OneOf.Extended/OneOfT21.generated.cs
+++ b/OneOf.Extended/OneOfT21.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -336,6 +339,123 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21)
         {
             if (_index == 0 && f0 != null)
@@ -429,6 +549,101 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> FromT2(T2 input) => input;
@@ -461,7 +676,637 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => mapFunc(AsT0),
+                0 => mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
@@ -470,7 +1315,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => AsT9,
+                9 => mapFunc(AsT9),
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -486,8 +1331,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT1<TResult>(Func<T1, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -496,7 +1342,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => mapFunc(AsT1),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -504,7 +1350,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => AsT9,
+                9 => await mapFunc(AsT9),
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -520,8 +1366,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT10<TResult>(Func<T10, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -531,7 +1378,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => mapFunc(AsT2),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -539,7 +1386,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => AsT10,
+                10 => mapFunc(AsT10),
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -554,8 +1401,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT3<TResult>(Func<T3, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -566,14 +1414,14 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => AsT10,
+                10 => await mapFunc(AsT10),
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -588,8 +1436,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT11<TResult>(Func<T11, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -601,14 +1450,14 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => AsT11,
+                11 => mapFunc(AsT11),
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -622,8 +1471,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT5<TResult>(Func<T5, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -636,13 +1486,13 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => AsT11,
+                11 => await mapFunc(AsT11),
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -656,8 +1506,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT12<TResult>(Func<T12, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -671,13 +1522,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => AsT12,
+                12 => mapFunc(AsT12),
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -690,8 +1541,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT7<TResult>(Func<T7, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -706,12 +1558,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => AsT12,
+                12 => await mapFunc(AsT12),
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -724,8 +1576,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21> MapT13<TResult>(Func<T13, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -741,12 +1594,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -758,8 +1611,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT9<TResult>(Func<T9, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -776,11 +1630,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => await mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -792,8 +1646,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21> MapT14<TResult>(Func<T14, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -811,11 +1666,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -826,8 +1681,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT11<TResult>(Func<T11, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -846,10 +1702,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => await mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -860,8 +1716,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21> MapT15<TResult>(Func<T15, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -881,10 +1738,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -894,8 +1751,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21> MapT13<TResult>(Func<T13, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -916,9 +1774,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => await mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -928,8 +1786,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21> MapT16<TResult>(Func<T16, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -951,9 +1810,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -962,8 +1821,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21> MapT15<TResult>(Func<T15, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -986,8 +1846,8 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
-                16 => AsT16,
+                15 => AsT15,
+                16 => await mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -996,8 +1856,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21> MapT17<TResult>(Func<T17, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1021,8 +1882,8 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
-                17 => AsT17,
+                16 => AsT16,
+                17 => mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -1030,8 +1891,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21> MapT17<TResult>(Func<T17, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1056,7 +1918,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
+                17 => await mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -1064,6 +1926,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21> MapT18<TResult>(Func<T18, TResult> mapFunc)
         {
@@ -1098,6 +1961,42 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => await mapFunc(AsT18),
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21> MapT19<TResult>(Func<T19, TResult> mapFunc)
         {
@@ -1132,6 +2031,42 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21>> MapT19Async<TResult>(Func<T19, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => await mapFunc(AsT19),
+                20 => AsT20,
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21> MapT20<TResult>(Func<T20, TResult> mapFunc)
         {
@@ -1166,6 +2101,42 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21>> MapT20Async<TResult>(Func<T20, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => await mapFunc(AsT20),
+                21 => AsT21,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult> MapT21<TResult>(Func<T21, TResult> mapFunc)
         {
@@ -1201,6 +2172,42 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult>> MapT21Async<TResult>(Func<T21, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => await mapFunc(AsT21),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT22.generated.cs b/OneOf.Extended/OneOfT22.generated.cs
index 58f9f5d..a659a94 100644
--- a/OneOf.Extended/OneOfT22.generated.cs
+++ b/OneOf.Extended/OneOfT22.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -350,6 +353,128 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22)
         {
             if (_index == 0 && f0 != null)
@@ -447,6 +572,105 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> FromT2(T2 input) => input;
@@ -471,8 +695,692 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> FromT21(T21 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> FromT22(T22 input) => input;
 
-        
-        public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT0<TResult>(Func<T0, TResult> mapFunc)
+        
+        public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT0<TResult>(Func<T0, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -480,7 +1388,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => mapFunc(AsT0),
+                0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
@@ -489,7 +1397,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => AsT9,
+                9 => await mapFunc(AsT9),
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -506,8 +1414,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT10<TResult>(Func<T10, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -516,7 +1425,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => mapFunc(AsT1),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -525,7 +1434,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => AsT10,
+                10 => mapFunc(AsT10),
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -541,8 +1450,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT2<TResult>(Func<T2, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -552,7 +1462,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => mapFunc(AsT2),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -560,7 +1470,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => AsT10,
+                10 => await mapFunc(AsT10),
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -576,8 +1486,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT11<TResult>(Func<T11, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -588,7 +1499,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -596,7 +1507,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => AsT11,
+                11 => mapFunc(AsT11),
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -611,8 +1522,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT4<TResult>(Func<T4, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -624,14 +1536,14 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => AsT11,
+                11 => await mapFunc(AsT11),
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -646,8 +1558,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT12<TResult>(Func<T12, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -660,14 +1573,14 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => AsT12,
+                12 => mapFunc(AsT12),
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -681,8 +1594,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT6<TResult>(Func<T6, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -696,13 +1610,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => AsT12,
+                12 => await mapFunc(AsT12),
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -716,8 +1630,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT13<TResult>(Func<T13, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -732,13 +1647,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -751,8 +1666,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT8<TResult>(Func<T8, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -768,12 +1684,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => await mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -786,8 +1702,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22> MapT14<TResult>(Func<T14, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -804,12 +1721,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -821,8 +1738,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT10<TResult>(Func<T10, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -840,11 +1758,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => await mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -856,8 +1774,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22> MapT15<TResult>(Func<T15, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -876,11 +1795,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -891,8 +1810,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT12<TResult>(Func<T12, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -912,10 +1832,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => await mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -926,8 +1846,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22> MapT16<TResult>(Func<T16, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -948,10 +1869,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -961,8 +1882,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22> MapT14<TResult>(Func<T14, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -984,9 +1906,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => await mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -996,8 +1918,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22> MapT17<TResult>(Func<T17, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1020,9 +1943,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -1031,8 +1954,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22> MapT16<TResult>(Func<T16, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1056,8 +1980,8 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
-                17 => AsT17,
+                16 => AsT16,
+                17 => await mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -1066,8 +1990,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22> MapT17<TResult>(Func<T17, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22> MapT18<TResult>(Func<T18, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1092,8 +2017,8 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
-                18 => AsT18,
+                17 => AsT17,
+                18 => mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1101,8 +2026,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22> MapT18<TResult>(Func<T18, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1128,7 +2054,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => mapFunc(AsT18),
+                18 => await mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1136,6 +2062,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22> MapT19<TResult>(Func<T19, TResult> mapFunc)
         {
@@ -1171,6 +2098,43 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22>> MapT19Async<TResult>(Func<T19, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => await mapFunc(AsT19),
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22> MapT20<TResult>(Func<T20, TResult> mapFunc)
         {
@@ -1206,6 +2170,43 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22>> MapT20Async<TResult>(Func<T20, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => await mapFunc(AsT20),
+                21 => AsT21,
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22> MapT21<TResult>(Func<T21, TResult> mapFunc)
         {
@@ -1241,6 +2242,43 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22>> MapT21Async<TResult>(Func<T21, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => await mapFunc(AsT21),
+                22 => AsT22,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult> MapT22<TResult>(Func<T22, TResult> mapFunc)
         {
@@ -1277,6 +2315,43 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult>> MapT22Async<TResult>(Func<T22, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => await mapFunc(AsT22),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT23.generated.cs b/OneOf.Extended/OneOfT23.generated.cs
index aa8881c..fac4c11 100644
--- a/OneOf.Extended/OneOfT23.generated.cs
+++ b/OneOf.Extended/OneOfT23.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -364,6 +367,133 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23)
         {
             if (_index == 0 && f0 != null)
@@ -465,6 +595,109 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> FromT2(T2 input) => input;
@@ -499,7 +732,747 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => mapFunc(AsT0),
+                0 => mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
@@ -509,7 +1482,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => AsT10,
+                10 => mapFunc(AsT10),
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -526,8 +1499,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT1<TResult>(Func<T1, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -536,7 +1510,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => mapFunc(AsT1),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -545,7 +1519,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => AsT10,
+                10 => await mapFunc(AsT10),
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -562,8 +1536,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT11<TResult>(Func<T11, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -573,7 +1548,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => mapFunc(AsT2),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -582,7 +1557,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => AsT11,
+                11 => mapFunc(AsT11),
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -598,8 +1573,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT3<TResult>(Func<T3, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -610,7 +1586,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -618,7 +1594,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => AsT11,
+                11 => await mapFunc(AsT11),
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -634,8 +1610,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT12<TResult>(Func<T12, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -647,7 +1624,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -655,7 +1632,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => AsT12,
+                12 => mapFunc(AsT12),
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -670,8 +1647,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT5<TResult>(Func<T5, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -684,14 +1662,14 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => AsT12,
+                12 => await mapFunc(AsT12),
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -706,8 +1684,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT13<TResult>(Func<T13, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -721,14 +1700,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -742,8 +1721,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT7<TResult>(Func<T7, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -758,13 +1738,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => await mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -778,8 +1758,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT14<TResult>(Func<T14, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -795,13 +1776,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -814,8 +1795,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT9<TResult>(Func<T9, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -832,12 +1814,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => await mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -850,8 +1832,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23> MapT15<TResult>(Func<T15, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -869,12 +1852,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -886,8 +1869,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT11<TResult>(Func<T11, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -906,11 +1890,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => await mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -922,8 +1906,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23> MapT16<TResult>(Func<T16, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -943,11 +1928,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -958,8 +1943,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT13<TResult>(Func<T13, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -980,10 +1966,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => await mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -994,8 +1980,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23> MapT17<TResult>(Func<T17, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1017,10 +2004,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -1030,8 +2017,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23> MapT15<TResult>(Func<T15, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1054,9 +2042,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => await mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -1066,8 +2054,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23> MapT18<TResult>(Func<T18, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1091,9 +2080,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1102,8 +2091,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23> MapT17<TResult>(Func<T17, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1128,8 +2118,8 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
-                18 => AsT18,
+                17 => AsT17,
+                18 => await mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1138,8 +2128,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23> MapT18<TResult>(Func<T18, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23> MapT19<TResult>(Func<T19, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1165,8 +2156,8 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => mapFunc(AsT18),
-                19 => AsT19,
+                18 => AsT18,
+                19 => mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1174,8 +2165,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23> MapT19<TResult>(Func<T19, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23>> MapT19Async<TResult>(Func<T19, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1202,7 +2194,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => mapFunc(AsT19),
+                19 => await mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1210,6 +2202,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23> MapT20<TResult>(Func<T20, TResult> mapFunc)
         {
@@ -1246,6 +2239,44 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23>> MapT20Async<TResult>(Func<T20, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => await mapFunc(AsT20),
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23> MapT21<TResult>(Func<T21, TResult> mapFunc)
         {
@@ -1282,6 +2313,44 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23>> MapT21Async<TResult>(Func<T21, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => await mapFunc(AsT21),
+                22 => AsT22,
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23> MapT22<TResult>(Func<T22, TResult> mapFunc)
         {
@@ -1318,6 +2387,44 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23>> MapT22Async<TResult>(Func<T22, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => await mapFunc(AsT22),
+                23 => AsT23,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult> MapT23<TResult>(Func<T23, TResult> mapFunc)
         {
@@ -1355,6 +2462,44 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult>> MapT23Async<TResult>(Func<T23, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => await mapFunc(AsT23),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT24.generated.cs b/OneOf.Extended/OneOfT24.generated.cs
index 87854ed..4ac5d6e 100644
--- a/OneOf.Extended/OneOfT24.generated.cs
+++ b/OneOf.Extended/OneOfT24.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -378,6 +381,138 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24)
         {
             if (_index == 0 && f0 != null)
@@ -483,6 +618,113 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> FromT2(T2 input) => input;
@@ -518,7 +760,843 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => mapFunc(AsT0),
+                0 => mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
@@ -529,7 +1607,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => AsT11,
+                11 => mapFunc(AsT11),
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -546,8 +1624,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT1<TResult>(Func<T1, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -556,7 +1635,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => mapFunc(AsT1),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -566,7 +1645,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => AsT11,
+                11 => await mapFunc(AsT11),
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -583,8 +1662,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT12<TResult>(Func<T12, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -594,7 +1674,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => mapFunc(AsT2),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -604,7 +1684,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => AsT12,
+                12 => mapFunc(AsT12),
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -620,8 +1700,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT3<TResult>(Func<T3, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -632,7 +1713,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -641,7 +1722,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => AsT12,
+                12 => await mapFunc(AsT12),
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -657,8 +1738,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT13<TResult>(Func<T13, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -670,7 +1752,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -679,7 +1761,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -694,8 +1776,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT5<TResult>(Func<T5, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -708,7 +1791,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -716,7 +1799,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => await mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -731,8 +1814,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT14<TResult>(Func<T14, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -746,7 +1830,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -754,7 +1838,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -768,8 +1852,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT7<TResult>(Func<T7, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -784,14 +1869,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => await mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -805,8 +1890,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT15<TResult>(Func<T15, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -822,14 +1908,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -842,8 +1928,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT9<TResult>(Func<T9, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -860,13 +1947,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => await mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -879,8 +1966,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24> MapT16<TResult>(Func<T16, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -898,13 +1986,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -916,8 +2004,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT11<TResult>(Func<T11, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -936,12 +2025,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => await mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -953,8 +2042,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24> MapT17<TResult>(Func<T17, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -974,12 +2064,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -990,8 +2080,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT13<TResult>(Func<T13, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1012,11 +2103,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => await mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -1027,8 +2118,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24> MapT18<TResult>(Func<T18, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1050,11 +2142,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1064,8 +2156,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24> MapT15<TResult>(Func<T15, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1088,10 +2181,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => await mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1101,8 +2194,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24> MapT19<TResult>(Func<T19, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1126,10 +2220,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1138,8 +2232,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24> MapT17<TResult>(Func<T17, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24>> MapT19Async<TResult>(Func<T19, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1164,9 +2259,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
+                17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => await mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1175,8 +2270,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24> MapT18<TResult>(Func<T18, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24> MapT20<TResult>(Func<T20, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1202,9 +2298,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => mapFunc(AsT18),
+                18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1212,8 +2308,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24> MapT19<TResult>(Func<T19, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24>> MapT20Async<TResult>(Func<T20, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1240,8 +2337,8 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => mapFunc(AsT19),
-                20 => AsT20,
+                19 => AsT19,
+                20 => await mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1249,8 +2346,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24> MapT20<TResult>(Func<T20, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24> MapT21<TResult>(Func<T21, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1278,16 +2376,17 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => mapFunc(AsT20),
-                21 => AsT21,
+                20 => AsT20,
+                21 => mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24> MapT21<TResult>(Func<T21, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24>> MapT21Async<TResult>(Func<T21, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1316,13 +2415,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => mapFunc(AsT21),
+                21 => await mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24> MapT22<TResult>(Func<T22, TResult> mapFunc)
         {
@@ -1360,6 +2460,45 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24>> MapT22Async<TResult>(Func<T22, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => await mapFunc(AsT22),
+                23 => AsT23,
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24> MapT23<TResult>(Func<T23, TResult> mapFunc)
         {
@@ -1397,6 +2536,45 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24>> MapT23Async<TResult>(Func<T23, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => await mapFunc(AsT23),
+                24 => AsT24,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult> MapT24<TResult>(Func<T24, TResult> mapFunc)
         {
@@ -1435,6 +2613,45 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult>> MapT24Async<TResult>(Func<T24, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => await mapFunc(AsT24),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT25.generated.cs b/OneOf.Extended/OneOfT25.generated.cs
index dcc509c..94aad4d 100644
--- a/OneOf.Extended/OneOfT25.generated.cs
+++ b/OneOf.Extended/OneOfT25.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -392,6 +395,143 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25)
         {
             if (_index == 0 && f0 != null)
@@ -501,6 +641,117 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> FromT2(T2 input) => input;
@@ -528,8 +779,905 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> FromT24(T24 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> FromT25(T25 input) => input;
 
-        
-        public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT0<TResult>(Func<T0, TResult> mapFunc)
+        
+        public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT0<TResult>(Func<T0, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -537,7 +1685,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => mapFunc(AsT0),
+                0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
@@ -548,7 +1696,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => AsT11,
+                11 => await mapFunc(AsT11),
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -566,8 +1714,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT12<TResult>(Func<T12, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -576,7 +1725,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => mapFunc(AsT1),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -587,7 +1736,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => AsT12,
+                12 => mapFunc(AsT12),
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -604,8 +1753,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT2<TResult>(Func<T2, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -615,7 +1765,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => mapFunc(AsT2),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -625,7 +1775,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => AsT12,
+                12 => await mapFunc(AsT12),
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -642,8 +1792,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT13<TResult>(Func<T13, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -654,7 +1805,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -664,7 +1815,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -680,8 +1831,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT4<TResult>(Func<T4, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -693,7 +1845,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -702,7 +1854,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => await mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -718,8 +1870,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT14<TResult>(Func<T14, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -732,7 +1885,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -741,7 +1894,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -756,8 +1909,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT6<TResult>(Func<T6, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -771,7 +1925,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -779,7 +1933,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => await mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -794,8 +1948,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT15<TResult>(Func<T15, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -810,7 +1965,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -818,7 +1973,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -832,8 +1987,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT8<TResult>(Func<T8, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -849,14 +2005,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => await mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -870,8 +2026,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT16<TResult>(Func<T16, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -888,14 +2045,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -908,8 +2065,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT10<TResult>(Func<T10, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -927,13 +2085,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => await mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -946,8 +2104,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25> MapT17<TResult>(Func<T17, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -966,13 +2125,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -984,8 +2143,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT12<TResult>(Func<T12, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1005,12 +2165,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => await mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -1022,8 +2182,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25> MapT18<TResult>(Func<T18, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1044,12 +2205,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1060,8 +2221,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT14<TResult>(Func<T14, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1083,11 +2245,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => await mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1098,8 +2260,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25> MapT19<TResult>(Func<T19, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1122,11 +2285,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1136,8 +2299,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25> MapT16<TResult>(Func<T16, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25>> MapT19Async<TResult>(Func<T19, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1161,10 +2325,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => await mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1174,8 +2338,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25> MapT17<TResult>(Func<T17, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25> MapT20<TResult>(Func<T20, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1200,10 +2365,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
+                17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1212,8 +2377,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25> MapT18<TResult>(Func<T18, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25>> MapT20Async<TResult>(Func<T20, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1239,9 +2405,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => mapFunc(AsT18),
+                18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => await mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1250,8 +2416,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25> MapT19<TResult>(Func<T19, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25> MapT21<TResult>(Func<T21, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1278,9 +2445,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => mapFunc(AsT19),
+                19 => AsT19,
                 20 => AsT20,
-                21 => AsT21,
+                21 => mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1288,8 +2455,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25> MapT20<TResult>(Func<T20, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25>> MapT21Async<TResult>(Func<T21, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1317,8 +2485,8 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => mapFunc(AsT20),
-                21 => AsT21,
+                20 => AsT20,
+                21 => await mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1326,8 +2494,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25> MapT21<TResult>(Func<T21, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25> MapT22<TResult>(Func<T22, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1356,16 +2525,17 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => mapFunc(AsT21),
-                22 => AsT22,
+                21 => AsT21,
+                22 => mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25> MapT22<TResult>(Func<T22, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25>> MapT22Async<TResult>(Func<T22, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1395,13 +2565,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => mapFunc(AsT22),
+                22 => await mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25> MapT23<TResult>(Func<T23, TResult> mapFunc)
         {
@@ -1440,6 +2611,46 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25>> MapT23Async<TResult>(Func<T23, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => await mapFunc(AsT23),
+                24 => AsT24,
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25> MapT24<TResult>(Func<T24, TResult> mapFunc)
         {
@@ -1478,6 +2689,46 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25>> MapT24Async<TResult>(Func<T24, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => await mapFunc(AsT24),
+                25 => AsT25,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult> MapT25<TResult>(Func<T25, TResult> mapFunc)
         {
@@ -1517,6 +2768,46 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult>> MapT25Async<TResult>(Func<T25, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => await mapFunc(AsT25),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT26.generated.cs b/OneOf.Extended/OneOfT26.generated.cs
index a70fda0..596e1df 100644
--- a/OneOf.Extended/OneOfT26.generated.cs
+++ b/OneOf.Extended/OneOfT26.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -406,6 +409,148 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25, Func<T26,Task> f26)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            if (_index == 26 && f26 != null)
+            {
+                await f26(_value26);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25, Func<T26, TResult> f26)
         {
             if (_index == 0 && f0 != null)
@@ -519,6 +664,121 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25, Func<T26, Task<TResult>> f26)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            if (_index == 26 && f26 != null)
+            {
+                return await f26(_value26);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> FromT2(T2 input) => input;
@@ -556,7 +816,967 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => mapFunc(AsT0),
+                0 => mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
@@ -568,7 +1788,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => AsT12,
+                12 => mapFunc(AsT12),
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -586,8 +1806,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT1<TResult>(Func<T1, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -596,7 +1817,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => mapFunc(AsT1),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -607,7 +1828,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => AsT12,
+                12 => await mapFunc(AsT12),
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -625,8 +1846,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT13<TResult>(Func<T13, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -636,7 +1858,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => mapFunc(AsT2),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -647,7 +1869,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -664,8 +1886,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT3<TResult>(Func<T3, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -676,7 +1899,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -686,7 +1909,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => await mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -703,8 +1926,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT14<TResult>(Func<T14, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -716,7 +1940,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -726,7 +1950,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -742,8 +1966,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT5<TResult>(Func<T5, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -756,7 +1981,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -765,7 +1990,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => await mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -781,8 +2006,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT15<TResult>(Func<T15, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -796,7 +2022,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -805,7 +2031,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -820,8 +2046,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT7<TResult>(Func<T7, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -836,7 +2063,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -844,7 +2071,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => await mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -859,8 +2086,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT16<TResult>(Func<T16, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -876,7 +2104,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -884,7 +2112,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -898,8 +2126,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT9<TResult>(Func<T9, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -916,14 +2145,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => await mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -937,8 +2166,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT17<TResult>(Func<T17, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -956,14 +2186,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -976,8 +2206,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT11<TResult>(Func<T11, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -996,13 +2227,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => await mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -1015,8 +2246,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26> MapT18<TResult>(Func<T18, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1036,13 +2268,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1054,8 +2286,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT13<TResult>(Func<T13, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1076,12 +2309,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => await mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1093,8 +2326,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26> MapT19<TResult>(Func<T19, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1116,12 +2350,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1132,8 +2366,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT15<TResult>(Func<T15, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26>> MapT19Async<TResult>(Func<T19, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1156,11 +2391,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => await mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1171,8 +2406,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26> MapT20<TResult>(Func<T20, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1196,11 +2432,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1210,8 +2446,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26> MapT17<TResult>(Func<T17, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26>> MapT20Async<TResult>(Func<T20, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1236,10 +2473,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
+                17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => await mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1249,8 +2486,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26> MapT18<TResult>(Func<T18, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26> MapT21<TResult>(Func<T21, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1276,10 +2514,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => mapFunc(AsT18),
+                18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => AsT21,
+                21 => mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1288,8 +2526,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26> MapT19<TResult>(Func<T19, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26>> MapT21Async<TResult>(Func<T21, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1316,9 +2555,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => mapFunc(AsT19),
+                19 => AsT19,
                 20 => AsT20,
-                21 => AsT21,
+                21 => await mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1327,8 +2566,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26> MapT20<TResult>(Func<T20, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26> MapT22<TResult>(Func<T22, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1356,9 +2596,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => mapFunc(AsT20),
+                20 => AsT20,
                 21 => AsT21,
-                22 => AsT22,
+                22 => mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
@@ -1366,8 +2606,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26> MapT21<TResult>(Func<T21, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26>> MapT22Async<TResult>(Func<T22, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1396,8 +2637,8 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => mapFunc(AsT21),
-                22 => AsT22,
+                21 => AsT21,
+                22 => await mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
@@ -1405,8 +2646,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26> MapT22<TResult>(Func<T22, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26> MapT23<TResult>(Func<T23, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1436,16 +2678,17 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => mapFunc(AsT22),
-                23 => AsT23,
+                22 => AsT22,
+                23 => mapFunc(AsT23),
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26> MapT23<TResult>(Func<T23, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26>> MapT23Async<TResult>(Func<T23, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1476,13 +2719,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => mapFunc(AsT23),
+                23 => await mapFunc(AsT23),
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26> MapT24<TResult>(Func<T24, TResult> mapFunc)
         {
@@ -1522,6 +2766,47 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26>> MapT24Async<TResult>(Func<T24, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => await mapFunc(AsT24),
+                25 => AsT25,
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26> MapT25<TResult>(Func<T25, TResult> mapFunc)
         {
@@ -1561,6 +2846,47 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26>> MapT25Async<TResult>(Func<T25, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => await mapFunc(AsT25),
+                26 => AsT26,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult> MapT26<TResult>(Func<T26, TResult> mapFunc)
         {
@@ -1601,6 +2927,47 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult>> MapT26Async<TResult>(Func<T26, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => await mapFunc(AsT26),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT27.generated.cs b/OneOf.Extended/OneOfT27.generated.cs
index fc45eab..9ec18c9 100644
--- a/OneOf.Extended/OneOfT27.generated.cs
+++ b/OneOf.Extended/OneOfT27.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -420,6 +423,153 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25, Func<T26,Task> f26, Func<T27,Task> f27)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            if (_index == 26 && f26 != null)
+            {
+                await f26(_value26);
+                return;
+            }
+            if (_index == 27 && f27 != null)
+            {
+                await f27(_value27);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25, Func<T26, TResult> f26, Func<T27, TResult> f27)
         {
             if (_index == 0 && f0 != null)
@@ -537,6 +687,125 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25, Func<T26, Task<TResult>> f26, Func<T27, Task<TResult>> f27)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            if (_index == 26 && f26 != null)
+            {
+                return await f26(_value26);
+            }
+            if (_index == 27 && f27 != null)
+            {
+                return await f27(_value27);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> FromT2(T2 input) => input;
@@ -575,7 +844,1073 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => mapFunc(AsT0),
+                0 => mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
@@ -588,7 +1923,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -606,8 +1941,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT1<TResult>(Func<T1, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -616,7 +1952,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => mapFunc(AsT1),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -628,7 +1964,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => await mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -646,8 +1982,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT14<TResult>(Func<T14, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -657,7 +1994,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => mapFunc(AsT2),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -669,7 +2006,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -686,8 +2023,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT3<TResult>(Func<T3, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -698,7 +2036,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -709,7 +2047,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => await mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -726,8 +2064,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT15<TResult>(Func<T15, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -739,7 +2078,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -750,7 +2089,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -766,8 +2105,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT5<TResult>(Func<T5, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -780,7 +2120,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -790,7 +2130,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => await mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -806,8 +2146,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT16<TResult>(Func<T16, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -821,7 +2162,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -831,7 +2172,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -846,8 +2187,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT7<TResult>(Func<T7, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -862,7 +2204,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -871,7 +2213,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => await mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -886,8 +2228,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT17<TResult>(Func<T17, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -903,7 +2246,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -912,7 +2255,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -926,8 +2269,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT9<TResult>(Func<T9, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -944,7 +2288,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -952,7 +2296,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => await mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -966,8 +2310,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT18<TResult>(Func<T18, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -985,7 +2330,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -993,7 +2338,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1006,8 +2351,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT11<TResult>(Func<T11, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1026,14 +2372,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => await mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1046,8 +2392,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27> MapT19<TResult>(Func<T19, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1067,14 +2414,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1086,8 +2433,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT13<TResult>(Func<T13, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27>> MapT19Async<TResult>(Func<T19, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1108,13 +2456,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => await mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1126,8 +2474,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27> MapT20<TResult>(Func<T20, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1149,13 +2498,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1166,8 +2515,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT15<TResult>(Func<T15, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27>> MapT20Async<TResult>(Func<T20, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1190,12 +2540,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => await mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1206,8 +2556,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27> MapT21<TResult>(Func<T21, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1231,12 +2582,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => AsT21,
+                21 => mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1246,8 +2597,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT17<TResult>(Func<T17, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27>> MapT21Async<TResult>(Func<T21, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1272,11 +2624,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
+                17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => AsT21,
+                21 => await mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1286,8 +2638,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27> MapT18<TResult>(Func<T18, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27> MapT22<TResult>(Func<T22, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1313,11 +2666,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => mapFunc(AsT18),
+                18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => AsT22,
+                22 => mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
@@ -1326,8 +2679,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27> MapT19<TResult>(Func<T19, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27>> MapT22Async<TResult>(Func<T22, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1354,10 +2708,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => mapFunc(AsT19),
+                19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => AsT22,
+                22 => await mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
@@ -1366,8 +2720,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27> MapT20<TResult>(Func<T20, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27> MapT23<TResult>(Func<T23, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1395,10 +2750,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => mapFunc(AsT20),
+                20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => AsT23,
+                23 => mapFunc(AsT23),
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
@@ -1406,8 +2761,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27> MapT21<TResult>(Func<T21, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27>> MapT23Async<TResult>(Func<T23, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1436,9 +2792,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => mapFunc(AsT21),
+                21 => AsT21,
                 22 => AsT22,
-                23 => AsT23,
+                23 => await mapFunc(AsT23),
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
@@ -1446,8 +2802,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27> MapT22<TResult>(Func<T22, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27> MapT24<TResult>(Func<T24, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1477,17 +2834,18 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => mapFunc(AsT22),
+                22 => AsT22,
                 23 => AsT23,
-                24 => AsT24,
+                24 => mapFunc(AsT24),
                 25 => AsT25,
                 26 => AsT26,
                 27 => AsT27,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27> MapT23<TResult>(Func<T23, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27>> MapT24Async<TResult>(Func<T24, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1518,16 +2876,17 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => mapFunc(AsT23),
-                24 => AsT24,
+                23 => AsT23,
+                24 => await mapFunc(AsT24),
                 25 => AsT25,
                 26 => AsT26,
                 27 => AsT27,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27> MapT24<TResult>(Func<T24, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27> MapT25<TResult>(Func<T25, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1559,15 +2918,16 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
-                24 => mapFunc(AsT24),
-                25 => AsT25,
+                24 => AsT24,
+                25 => mapFunc(AsT25),
                 26 => AsT26,
                 27 => AsT27,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27> MapT25<TResult>(Func<T25, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27>> MapT25Async<TResult>(Func<T25, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1600,12 +2960,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
-                25 => mapFunc(AsT25),
+                25 => await mapFunc(AsT25),
                 26 => AsT26,
                 27 => AsT27,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27> MapT26<TResult>(Func<T26, TResult> mapFunc)
         {
@@ -1646,6 +3007,48 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27>> MapT26Async<TResult>(Func<T26, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => await mapFunc(AsT26),
+                27 => AsT27,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, TResult> MapT27<TResult>(Func<T27, TResult> mapFunc)
         {
@@ -1687,6 +3090,48 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, TResult>> MapT27Async<TResult>(Func<T27, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => await mapFunc(AsT27),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT28.generated.cs b/OneOf.Extended/OneOfT28.generated.cs
index bdaa11f..1eb5566 100644
--- a/OneOf.Extended/OneOfT28.generated.cs
+++ b/OneOf.Extended/OneOfT28.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -434,6 +437,158 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25, Func<T26,Task> f26, Func<T27,Task> f27, Func<T28,Task> f28)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            if (_index == 26 && f26 != null)
+            {
+                await f26(_value26);
+                return;
+            }
+            if (_index == 27 && f27 != null)
+            {
+                await f27(_value27);
+                return;
+            }
+            if (_index == 28 && f28 != null)
+            {
+                await f28(_value28);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25, Func<T26, TResult> f26, Func<T27, TResult> f27, Func<T28, TResult> f28)
         {
             if (_index == 0 && f0 != null)
@@ -555,6 +710,129 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25, Func<T26, Task<TResult>> f26, Func<T27, Task<TResult>> f27, Func<T28, Task<TResult>> f28)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            if (_index == 26 && f26 != null)
+            {
+                return await f26(_value26);
+            }
+            if (_index == 27 && f27 != null)
+            {
+                return await f27(_value27);
+            }
+            if (_index == 28 && f28 != null)
+            {
+                return await f28(_value28);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> FromT2(T2 input) => input;
@@ -585,8 +863,1142 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> FromT27(T27 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> FromT28(T28 input) => input;
 
-        
-        public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT0<TResult>(Func<T0, TResult> mapFunc)
+        
+        public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT0<TResult>(Func<T0, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -594,7 +2006,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => mapFunc(AsT0),
+                0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
@@ -607,7 +2019,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => AsT13,
+                13 => await mapFunc(AsT13),
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -626,8 +2038,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT14<TResult>(Func<T14, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -636,7 +2049,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => mapFunc(AsT1),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -649,7 +2062,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -667,8 +2080,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT2<TResult>(Func<T2, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -678,7 +2092,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => mapFunc(AsT2),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -690,7 +2104,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => await mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -708,8 +2122,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT15<TResult>(Func<T15, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -720,7 +2135,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -732,7 +2147,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -749,8 +2164,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT4<TResult>(Func<T4, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -762,7 +2178,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -773,7 +2189,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => await mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -790,8 +2206,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT16<TResult>(Func<T16, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -804,7 +2221,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -815,7 +2232,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -831,8 +2248,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT6<TResult>(Func<T6, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -846,7 +2264,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -856,7 +2274,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => await mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -872,8 +2290,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT17<TResult>(Func<T17, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -888,7 +2307,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -898,7 +2317,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -913,8 +2332,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT8<TResult>(Func<T8, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -930,7 +2350,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -939,7 +2359,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => await mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -954,8 +2374,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT18<TResult>(Func<T18, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -972,7 +2393,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -981,7 +2402,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -995,8 +2416,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT10<TResult>(Func<T10, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1014,7 +2436,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -1022,7 +2444,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => await mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1036,8 +2458,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT19<TResult>(Func<T19, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1056,7 +2479,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -1064,7 +2487,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1077,8 +2500,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT12<TResult>(Func<T12, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27, T28>> MapT19Async<TResult>(Func<T19, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1098,14 +2522,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => await mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1118,8 +2542,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27, T28> MapT20<TResult>(Func<T20, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1140,14 +2565,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1159,8 +2584,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT14<TResult>(Func<T14, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27, T28>> MapT20Async<TResult>(Func<T20, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1182,13 +2608,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => await mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1200,8 +2626,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27, T28> MapT21<TResult>(Func<T21, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1224,13 +2651,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => AsT21,
+                21 => mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1241,8 +2668,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT16<TResult>(Func<T16, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27, T28>> MapT21Async<TResult>(Func<T21, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1266,12 +2694,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => AsT21,
+                21 => await mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1282,8 +2710,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT17<TResult>(Func<T17, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27, T28> MapT22<TResult>(Func<T22, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1308,12 +2737,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
+                17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => AsT22,
+                22 => mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
@@ -1323,8 +2752,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT18<TResult>(Func<T18, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27, T28>> MapT22Async<TResult>(Func<T22, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1350,11 +2780,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => mapFunc(AsT18),
+                18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => AsT22,
+                22 => await mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
@@ -1364,8 +2794,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27, T28> MapT19<TResult>(Func<T19, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27, T28> MapT23<TResult>(Func<T23, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1392,11 +2823,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => mapFunc(AsT19),
+                19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => AsT23,
+                23 => mapFunc(AsT23),
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
@@ -1405,8 +2836,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27, T28> MapT20<TResult>(Func<T20, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27, T28>> MapT23Async<TResult>(Func<T23, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1434,10 +2866,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => mapFunc(AsT20),
+                20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => AsT23,
+                23 => await mapFunc(AsT23),
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
@@ -1446,8 +2878,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27, T28> MapT21<TResult>(Func<T21, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27, T28> MapT24<TResult>(Func<T24, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1476,10 +2909,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => mapFunc(AsT21),
+                21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
-                24 => AsT24,
+                24 => mapFunc(AsT24),
                 25 => AsT25,
                 26 => AsT26,
                 27 => AsT27,
@@ -1487,8 +2920,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27, T28> MapT22<TResult>(Func<T22, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27, T28>> MapT24Async<TResult>(Func<T24, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1518,9 +2952,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => mapFunc(AsT22),
+                22 => AsT22,
                 23 => AsT23,
-                24 => AsT24,
+                24 => await mapFunc(AsT24),
                 25 => AsT25,
                 26 => AsT26,
                 27 => AsT27,
@@ -1528,8 +2962,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27, T28> MapT23<TResult>(Func<T23, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27, T28> MapT25<TResult>(Func<T25, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1560,17 +2995,18 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => mapFunc(AsT23),
+                23 => AsT23,
                 24 => AsT24,
-                25 => AsT25,
+                25 => mapFunc(AsT25),
                 26 => AsT26,
                 27 => AsT27,
                 28 => AsT28,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27, T28> MapT24<TResult>(Func<T24, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27, T28>> MapT25Async<TResult>(Func<T25, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1602,16 +3038,17 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
-                24 => mapFunc(AsT24),
-                25 => AsT25,
+                24 => AsT24,
+                25 => await mapFunc(AsT25),
                 26 => AsT26,
                 27 => AsT27,
                 28 => AsT28,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27, T28> MapT25<TResult>(Func<T25, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27, T28> MapT26<TResult>(Func<T26, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1644,15 +3081,16 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
-                25 => mapFunc(AsT25),
-                26 => AsT26,
+                25 => AsT25,
+                26 => mapFunc(AsT26),
                 27 => AsT27,
                 28 => AsT28,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27, T28> MapT26<TResult>(Func<T26, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27, T28>> MapT26Async<TResult>(Func<T26, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1686,12 +3124,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
-                26 => mapFunc(AsT26),
+                26 => await mapFunc(AsT26),
                 27 => AsT27,
                 28 => AsT28,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, TResult, T28> MapT27<TResult>(Func<T27, TResult> mapFunc)
         {
@@ -1733,6 +3172,49 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, TResult, T28>> MapT27Async<TResult>(Func<T27, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => await mapFunc(AsT27),
+                28 => AsT28,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, TResult> MapT28<TResult>(Func<T28, TResult> mapFunc)
         {
@@ -1775,6 +3257,49 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, TResult>> MapT28Async<TResult>(Func<T28, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => await mapFunc(AsT28),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT29.generated.cs b/OneOf.Extended/OneOfT29.generated.cs
index 74ec58e..fbc9c19 100644
--- a/OneOf.Extended/OneOfT29.generated.cs
+++ b/OneOf.Extended/OneOfT29.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -448,6 +451,163 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25, Func<T26,Task> f26, Func<T27,Task> f27, Func<T28,Task> f28, Func<T29,Task> f29)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            if (_index == 26 && f26 != null)
+            {
+                await f26(_value26);
+                return;
+            }
+            if (_index == 27 && f27 != null)
+            {
+                await f27(_value27);
+                return;
+            }
+            if (_index == 28 && f28 != null)
+            {
+                await f28(_value28);
+                return;
+            }
+            if (_index == 29 && f29 != null)
+            {
+                await f29(_value29);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25, Func<T26, TResult> f26, Func<T27, TResult> f27, Func<T28, TResult> f28, Func<T29, TResult> f29)
         {
             if (_index == 0 && f0 != null)
@@ -573,6 +733,133 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25, Func<T26, Task<TResult>> f26, Func<T27, Task<TResult>> f27, Func<T28, Task<TResult>> f28, Func<T29, Task<TResult>> f29)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            if (_index == 26 && f26 != null)
+            {
+                return await f26(_value26);
+            }
+            if (_index == 27 && f27 != null)
+            {
+                return await f27(_value27);
+            }
+            if (_index == 28 && f28 != null)
+            {
+                return await f28(_value28);
+            }
+            if (_index == 29 && f29 != null)
+            {
+                return await f29(_value29);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> FromT2(T2 input) => input;
@@ -613,7 +900,1211 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => mapFunc(AsT0),
+                0 => mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => await mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
@@ -627,7 +2118,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -646,8 +2137,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT1<TResult>(Func<T1, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -656,7 +2148,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => mapFunc(AsT1),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -669,7 +2161,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => await mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -688,8 +2180,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT15<TResult>(Func<T15, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -699,7 +2192,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => mapFunc(AsT2),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -712,7 +2205,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -730,8 +2223,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT3<TResult>(Func<T3, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -742,7 +2236,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -754,7 +2248,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => await mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -772,8 +2266,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT16<TResult>(Func<T16, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -785,7 +2280,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -797,7 +2292,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -814,8 +2309,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT5<TResult>(Func<T5, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -828,7 +2324,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -839,7 +2335,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => await mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -856,8 +2352,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT17<TResult>(Func<T17, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -871,7 +2368,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -882,7 +2379,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -898,8 +2395,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT7<TResult>(Func<T7, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -914,7 +2412,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -924,7 +2422,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => await mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -940,8 +2438,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT18<TResult>(Func<T18, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -957,7 +2456,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -967,7 +2466,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -982,8 +2481,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT9<TResult>(Func<T9, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1000,7 +2500,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -1009,7 +2509,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => await mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1024,8 +2524,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT19<TResult>(Func<T19, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1043,7 +2544,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -1052,7 +2553,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1066,8 +2567,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT11<TResult>(Func<T11, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT19Async<TResult>(Func<T19, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1086,7 +2588,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -1094,7 +2596,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => await mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1108,8 +2610,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT20<TResult>(Func<T20, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1129,7 +2632,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -1137,7 +2640,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1150,8 +2653,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT13<TResult>(Func<T13, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27, T28, T29>> MapT20Async<TResult>(Func<T20, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1172,14 +2676,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => await mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1192,8 +2696,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27, T28, T29> MapT21<TResult>(Func<T21, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1215,14 +2720,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => AsT21,
+                21 => mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1234,8 +2739,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT15<TResult>(Func<T15, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27, T28, T29>> MapT21Async<TResult>(Func<T21, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1258,13 +2764,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => AsT21,
+                21 => await mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1276,8 +2782,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT16<TResult>(Func<T16, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27, T28, T29> MapT22<TResult>(Func<T22, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1301,13 +2808,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => AsT22,
+                22 => mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
@@ -1318,8 +2825,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT17<TResult>(Func<T17, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27, T28, T29>> MapT22Async<TResult>(Func<T22, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1344,12 +2852,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
+                17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => AsT22,
+                22 => await mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
@@ -1360,8 +2868,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT18<TResult>(Func<T18, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27, T28, T29> MapT23<TResult>(Func<T23, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1387,12 +2896,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => mapFunc(AsT18),
+                18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => AsT23,
+                23 => mapFunc(AsT23),
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
@@ -1402,8 +2911,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT19<TResult>(Func<T19, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27, T28, T29>> MapT23Async<TResult>(Func<T23, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1430,11 +2940,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => mapFunc(AsT19),
+                19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => AsT23,
+                23 => await mapFunc(AsT23),
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
@@ -1444,8 +2954,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27, T28, T29> MapT20<TResult>(Func<T20, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27, T28, T29> MapT24<TResult>(Func<T24, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1473,11 +2984,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => mapFunc(AsT20),
+                20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
-                24 => AsT24,
+                24 => mapFunc(AsT24),
                 25 => AsT25,
                 26 => AsT26,
                 27 => AsT27,
@@ -1486,8 +2997,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27, T28, T29> MapT21<TResult>(Func<T21, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27, T28, T29>> MapT24Async<TResult>(Func<T24, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1516,10 +3028,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => mapFunc(AsT21),
+                21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
-                24 => AsT24,
+                24 => await mapFunc(AsT24),
                 25 => AsT25,
                 26 => AsT26,
                 27 => AsT27,
@@ -1528,8 +3040,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27, T28, T29> MapT22<TResult>(Func<T22, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27, T28, T29> MapT25<TResult>(Func<T25, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1559,10 +3072,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => mapFunc(AsT22),
+                22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
-                25 => AsT25,
+                25 => mapFunc(AsT25),
                 26 => AsT26,
                 27 => AsT27,
                 28 => AsT28,
@@ -1570,8 +3083,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27, T28, T29> MapT23<TResult>(Func<T23, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27, T28, T29>> MapT25Async<TResult>(Func<T25, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1602,9 +3116,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => mapFunc(AsT23),
+                23 => AsT23,
                 24 => AsT24,
-                25 => AsT25,
+                25 => await mapFunc(AsT25),
                 26 => AsT26,
                 27 => AsT27,
                 28 => AsT28,
@@ -1612,8 +3126,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27, T28, T29> MapT24<TResult>(Func<T24, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27, T28, T29> MapT26<TResult>(Func<T26, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1645,17 +3160,18 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
-                24 => mapFunc(AsT24),
+                24 => AsT24,
                 25 => AsT25,
-                26 => AsT26,
+                26 => mapFunc(AsT26),
                 27 => AsT27,
                 28 => AsT28,
                 29 => AsT29,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27, T28, T29> MapT25<TResult>(Func<T25, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27, T28, T29>> MapT26Async<TResult>(Func<T26, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1688,16 +3204,17 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
-                25 => mapFunc(AsT25),
-                26 => AsT26,
+                25 => AsT25,
+                26 => await mapFunc(AsT26),
                 27 => AsT27,
                 28 => AsT28,
                 29 => AsT29,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27, T28, T29> MapT26<TResult>(Func<T26, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, TResult, T28, T29> MapT27<TResult>(Func<T27, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1731,15 +3248,16 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
-                26 => mapFunc(AsT26),
-                27 => AsT27,
+                26 => AsT26,
+                27 => mapFunc(AsT27),
                 28 => AsT28,
                 29 => AsT29,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, TResult, T28, T29> MapT27<TResult>(Func<T27, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, TResult, T28, T29>> MapT27Async<TResult>(Func<T27, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1774,12 +3292,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
-                27 => mapFunc(AsT27),
+                27 => await mapFunc(AsT27),
                 28 => AsT28,
                 29 => AsT29,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, TResult, T29> MapT28<TResult>(Func<T28, TResult> mapFunc)
         {
@@ -1822,6 +3341,50 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, TResult, T29>> MapT28Async<TResult>(Func<T28, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => await mapFunc(AsT28),
+                29 => AsT29,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, TResult> MapT29<TResult>(Func<T29, TResult> mapFunc)
         {
@@ -1865,6 +3428,50 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, TResult>> MapT29Async<TResult>(Func<T29, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => await mapFunc(AsT29),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT30.generated.cs b/OneOf.Extended/OneOfT30.generated.cs
index 5c6e763..c9859bf 100644
--- a/OneOf.Extended/OneOfT30.generated.cs
+++ b/OneOf.Extended/OneOfT30.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -462,6 +465,168 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25, Func<T26,Task> f26, Func<T27,Task> f27, Func<T28,Task> f28, Func<T29,Task> f29, Func<T30,Task> f30)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            if (_index == 26 && f26 != null)
+            {
+                await f26(_value26);
+                return;
+            }
+            if (_index == 27 && f27 != null)
+            {
+                await f27(_value27);
+                return;
+            }
+            if (_index == 28 && f28 != null)
+            {
+                await f28(_value28);
+                return;
+            }
+            if (_index == 29 && f29 != null)
+            {
+                await f29(_value29);
+                return;
+            }
+            if (_index == 30 && f30 != null)
+            {
+                await f30(_value30);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25, Func<T26, TResult> f26, Func<T27, TResult> f27, Func<T28, TResult> f28, Func<T29, TResult> f29, Func<T30, TResult> f30)
         {
             if (_index == 0 && f0 != null)
@@ -591,6 +756,137 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25, Func<T26, Task<TResult>> f26, Func<T27, Task<TResult>> f27, Func<T28, Task<TResult>> f28, Func<T29, Task<TResult>> f29, Func<T30, Task<TResult>> f30)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            if (_index == 26 && f26 != null)
+            {
+                return await f26(_value26);
+            }
+            if (_index == 27 && f27 != null)
+            {
+                return await f27(_value27);
+            }
+            if (_index == 28 && f28 != null)
+            {
+                return await f28(_value28);
+            }
+            if (_index == 29 && f29 != null)
+            {
+                return await f29(_value29);
+            }
+            if (_index == 30 && f30 != null)
+            {
+                return await f30(_value30);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> FromT2(T2 input) => input;
@@ -623,8 +919,1284 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> FromT29(T29 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> FromT30(T30 input) => input;
 
-        
-        public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT0<TResult>(Func<T0, TResult> mapFunc)
+        
+        public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT0<TResult>(Func<T0, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => await mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => mapFunc(AsT14),
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -632,7 +2204,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => mapFunc(AsT0),
+                0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
@@ -646,7 +2218,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => AsT14,
+                14 => await mapFunc(AsT14),
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -666,8 +2238,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT15<TResult>(Func<T15, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -676,7 +2249,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => mapFunc(AsT1),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -690,7 +2263,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -709,8 +2282,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT2<TResult>(Func<T2, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -720,7 +2294,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => mapFunc(AsT2),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -733,7 +2307,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => await mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -752,8 +2326,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT16<TResult>(Func<T16, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -764,7 +2339,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -777,7 +2352,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -795,8 +2370,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT4<TResult>(Func<T4, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -808,7 +2384,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -820,7 +2396,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => await mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -838,8 +2414,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT17<TResult>(Func<T17, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -852,7 +2429,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -864,7 +2441,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -881,8 +2458,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT6<TResult>(Func<T6, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -896,7 +2474,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -907,7 +2485,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => await mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -924,8 +2502,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT18<TResult>(Func<T18, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -940,7 +2519,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -951,7 +2530,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -967,8 +2546,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT8<TResult>(Func<T8, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -984,7 +2564,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -994,7 +2574,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => await mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -1010,8 +2590,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT19<TResult>(Func<T19, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1028,7 +2609,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -1038,7 +2619,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1053,8 +2634,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT10<TResult>(Func<T10, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT19Async<TResult>(Func<T19, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1072,7 +2654,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -1081,7 +2663,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => await mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1096,8 +2678,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT20<TResult>(Func<T20, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1116,7 +2699,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -1125,7 +2708,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1139,8 +2722,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT12<TResult>(Func<T12, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT20Async<TResult>(Func<T20, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1160,7 +2744,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -1168,7 +2752,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => await mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1182,8 +2766,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT21<TResult>(Func<T21, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1204,7 +2789,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -1212,7 +2797,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => AsT21,
+                21 => mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1225,8 +2810,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT14<TResult>(Func<T14, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27, T28, T29, T30>> MapT21Async<TResult>(Func<T21, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1248,14 +2834,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => AsT21,
+                21 => await mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1268,8 +2854,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27, T28, T29, T30> MapT22<TResult>(Func<T22, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1292,14 +2879,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => AsT22,
+                22 => mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
@@ -1311,8 +2898,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT16<TResult>(Func<T16, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27, T28, T29, T30>> MapT22Async<TResult>(Func<T22, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1336,13 +2924,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => AsT22,
+                22 => await mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
@@ -1354,8 +2942,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT17<TResult>(Func<T17, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27, T28, T29, T30> MapT23<TResult>(Func<T23, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1380,13 +2969,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
+                17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => AsT23,
+                23 => mapFunc(AsT23),
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
@@ -1397,8 +2986,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT18<TResult>(Func<T18, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27, T28, T29, T30>> MapT23Async<TResult>(Func<T23, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1424,12 +3014,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => mapFunc(AsT18),
+                18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => AsT23,
+                23 => await mapFunc(AsT23),
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
@@ -1440,8 +3030,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT19<TResult>(Func<T19, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27, T28, T29, T30> MapT24<TResult>(Func<T24, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1468,12 +3059,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => mapFunc(AsT19),
+                19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
-                24 => AsT24,
+                24 => mapFunc(AsT24),
                 25 => AsT25,
                 26 => AsT26,
                 27 => AsT27,
@@ -1483,8 +3074,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT20<TResult>(Func<T20, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27, T28, T29, T30>> MapT24Async<TResult>(Func<T24, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1512,11 +3104,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => mapFunc(AsT20),
+                20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
-                24 => AsT24,
+                24 => await mapFunc(AsT24),
                 25 => AsT25,
                 26 => AsT26,
                 27 => AsT27,
@@ -1526,8 +3118,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27, T28, T29, T30> MapT21<TResult>(Func<T21, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27, T28, T29, T30> MapT25<TResult>(Func<T25, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1556,11 +3149,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => mapFunc(AsT21),
+                21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
-                25 => AsT25,
+                25 => mapFunc(AsT25),
                 26 => AsT26,
                 27 => AsT27,
                 28 => AsT28,
@@ -1569,8 +3162,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27, T28, T29, T30> MapT22<TResult>(Func<T22, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27, T28, T29, T30>> MapT25Async<TResult>(Func<T25, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1600,10 +3194,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => mapFunc(AsT22),
+                22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
-                25 => AsT25,
+                25 => await mapFunc(AsT25),
                 26 => AsT26,
                 27 => AsT27,
                 28 => AsT28,
@@ -1612,8 +3206,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27, T28, T29, T30> MapT23<TResult>(Func<T23, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27, T28, T29, T30> MapT26<TResult>(Func<T26, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1644,10 +3239,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => mapFunc(AsT23),
+                23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
-                26 => AsT26,
+                26 => mapFunc(AsT26),
                 27 => AsT27,
                 28 => AsT28,
                 29 => AsT29,
@@ -1655,8 +3250,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27, T28, T29, T30> MapT24<TResult>(Func<T24, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27, T28, T29, T30>> MapT26Async<TResult>(Func<T26, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1688,9 +3284,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
-                24 => mapFunc(AsT24),
+                24 => AsT24,
                 25 => AsT25,
-                26 => AsT26,
+                26 => await mapFunc(AsT26),
                 27 => AsT27,
                 28 => AsT28,
                 29 => AsT29,
@@ -1698,8 +3294,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27, T28, T29, T30> MapT25<TResult>(Func<T25, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, TResult, T28, T29, T30> MapT27<TResult>(Func<T27, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1732,17 +3329,18 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
-                25 => mapFunc(AsT25),
+                25 => AsT25,
                 26 => AsT26,
-                27 => AsT27,
+                27 => mapFunc(AsT27),
                 28 => AsT28,
                 29 => AsT29,
                 30 => AsT30,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27, T28, T29, T30> MapT26<TResult>(Func<T26, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, TResult, T28, T29, T30>> MapT27Async<TResult>(Func<T27, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1776,16 +3374,17 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
-                26 => mapFunc(AsT26),
-                27 => AsT27,
+                26 => AsT26,
+                27 => await mapFunc(AsT27),
                 28 => AsT28,
                 29 => AsT29,
                 30 => AsT30,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, TResult, T28, T29, T30> MapT27<TResult>(Func<T27, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, TResult, T29, T30> MapT28<TResult>(Func<T28, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1820,15 +3419,16 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
-                27 => mapFunc(AsT27),
-                28 => AsT28,
+                27 => AsT27,
+                28 => mapFunc(AsT28),
                 29 => AsT29,
                 30 => AsT30,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, TResult, T29, T30> MapT28<TResult>(Func<T28, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, TResult, T29, T30>> MapT28Async<TResult>(Func<T28, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1864,12 +3464,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 25 => AsT25,
                 26 => AsT26,
                 27 => AsT27,
-                28 => mapFunc(AsT28),
+                28 => await mapFunc(AsT28),
                 29 => AsT29,
                 30 => AsT30,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, TResult, T30> MapT29<TResult>(Func<T29, TResult> mapFunc)
         {
@@ -1913,6 +3514,51 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, TResult, T30>> MapT29Async<TResult>(Func<T29, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => await mapFunc(AsT29),
+                30 => AsT30,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, TResult> MapT30<TResult>(Func<T30, TResult> mapFunc)
         {
@@ -1957,6 +3603,51 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, TResult>> MapT30Async<TResult>(Func<T30, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => await mapFunc(AsT30),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT31.generated.cs b/OneOf.Extended/OneOfT31.generated.cs
index 5e2686e..9b1b000 100644
--- a/OneOf.Extended/OneOfT31.generated.cs
+++ b/OneOf.Extended/OneOfT31.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -476,6 +479,173 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9, Func<T10,Task> f10, Func<T11,Task> f11, Func<T12,Task> f12, Func<T13,Task> f13, Func<T14,Task> f14, Func<T15,Task> f15, Func<T16,Task> f16, Func<T17,Task> f17, Func<T18,Task> f18, Func<T19,Task> f19, Func<T20,Task> f20, Func<T21,Task> f21, Func<T22,Task> f22, Func<T23,Task> f23, Func<T24,Task> f24, Func<T25,Task> f25, Func<T26,Task> f26, Func<T27,Task> f27, Func<T28,Task> f28, Func<T29,Task> f29, Func<T30,Task> f30, Func<T31,Task> f31)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            if (_index == 10 && f10 != null)
+            {
+                await f10(_value10);
+                return;
+            }
+            if (_index == 11 && f11 != null)
+            {
+                await f11(_value11);
+                return;
+            }
+            if (_index == 12 && f12 != null)
+            {
+                await f12(_value12);
+                return;
+            }
+            if (_index == 13 && f13 != null)
+            {
+                await f13(_value13);
+                return;
+            }
+            if (_index == 14 && f14 != null)
+            {
+                await f14(_value14);
+                return;
+            }
+            if (_index == 15 && f15 != null)
+            {
+                await f15(_value15);
+                return;
+            }
+            if (_index == 16 && f16 != null)
+            {
+                await f16(_value16);
+                return;
+            }
+            if (_index == 17 && f17 != null)
+            {
+                await f17(_value17);
+                return;
+            }
+            if (_index == 18 && f18 != null)
+            {
+                await f18(_value18);
+                return;
+            }
+            if (_index == 19 && f19 != null)
+            {
+                await f19(_value19);
+                return;
+            }
+            if (_index == 20 && f20 != null)
+            {
+                await f20(_value20);
+                return;
+            }
+            if (_index == 21 && f21 != null)
+            {
+                await f21(_value21);
+                return;
+            }
+            if (_index == 22 && f22 != null)
+            {
+                await f22(_value22);
+                return;
+            }
+            if (_index == 23 && f23 != null)
+            {
+                await f23(_value23);
+                return;
+            }
+            if (_index == 24 && f24 != null)
+            {
+                await f24(_value24);
+                return;
+            }
+            if (_index == 25 && f25 != null)
+            {
+                await f25(_value25);
+                return;
+            }
+            if (_index == 26 && f26 != null)
+            {
+                await f26(_value26);
+                return;
+            }
+            if (_index == 27 && f27 != null)
+            {
+                await f27(_value27);
+                return;
+            }
+            if (_index == 28 && f28 != null)
+            {
+                await f28(_value28);
+                return;
+            }
+            if (_index == 29 && f29 != null)
+            {
+                await f29(_value29);
+                return;
+            }
+            if (_index == 30 && f30 != null)
+            {
+                await f30(_value30);
+                return;
+            }
+            if (_index == 31 && f31 != null)
+            {
+                await f31(_value31);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9, Func<T10, TResult> f10, Func<T11, TResult> f11, Func<T12, TResult> f12, Func<T13, TResult> f13, Func<T14, TResult> f14, Func<T15, TResult> f15, Func<T16, TResult> f16, Func<T17, TResult> f17, Func<T18, TResult> f18, Func<T19, TResult> f19, Func<T20, TResult> f20, Func<T21, TResult> f21, Func<T22, TResult> f22, Func<T23, TResult> f23, Func<T24, TResult> f24, Func<T25, TResult> f25, Func<T26, TResult> f26, Func<T27, TResult> f27, Func<T28, TResult> f28, Func<T29, TResult> f29, Func<T30, TResult> f30, Func<T31, TResult> f31)
         {
             if (_index == 0 && f0 != null)
@@ -609,6 +779,141 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9, Func<T10, Task<TResult>> f10, Func<T11, Task<TResult>> f11, Func<T12, Task<TResult>> f12, Func<T13, Task<TResult>> f13, Func<T14, Task<TResult>> f14, Func<T15, Task<TResult>> f15, Func<T16, Task<TResult>> f16, Func<T17, Task<TResult>> f17, Func<T18, Task<TResult>> f18, Func<T19, Task<TResult>> f19, Func<T20, Task<TResult>> f20, Func<T21, Task<TResult>> f21, Func<T22, Task<TResult>> f22, Func<T23, Task<TResult>> f23, Func<T24, Task<TResult>> f24, Func<T25, Task<TResult>> f25, Func<T26, Task<TResult>> f26, Func<T27, Task<TResult>> f27, Func<T28, Task<TResult>> f28, Func<T29, Task<TResult>> f29, Func<T30, Task<TResult>> f30, Func<T31, Task<TResult>> f31)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            if (_index == 10 && f10 != null)
+            {
+                return await f10(_value10);
+            }
+            if (_index == 11 && f11 != null)
+            {
+                return await f11(_value11);
+            }
+            if (_index == 12 && f12 != null)
+            {
+                return await f12(_value12);
+            }
+            if (_index == 13 && f13 != null)
+            {
+                return await f13(_value13);
+            }
+            if (_index == 14 && f14 != null)
+            {
+                return await f14(_value14);
+            }
+            if (_index == 15 && f15 != null)
+            {
+                return await f15(_value15);
+            }
+            if (_index == 16 && f16 != null)
+            {
+                return await f16(_value16);
+            }
+            if (_index == 17 && f17 != null)
+            {
+                return await f17(_value17);
+            }
+            if (_index == 18 && f18 != null)
+            {
+                return await f18(_value18);
+            }
+            if (_index == 19 && f19 != null)
+            {
+                return await f19(_value19);
+            }
+            if (_index == 20 && f20 != null)
+            {
+                return await f20(_value20);
+            }
+            if (_index == 21 && f21 != null)
+            {
+                return await f21(_value21);
+            }
+            if (_index == 22 && f22 != null)
+            {
+                return await f22(_value22);
+            }
+            if (_index == 23 && f23 != null)
+            {
+                return await f23(_value23);
+            }
+            if (_index == 24 && f24 != null)
+            {
+                return await f24(_value24);
+            }
+            if (_index == 25 && f25 != null)
+            {
+                return await f25(_value25);
+            }
+            if (_index == 26 && f26 != null)
+            {
+                return await f26(_value26);
+            }
+            if (_index == 27 && f27 != null)
+            {
+                return await f27(_value27);
+            }
+            if (_index == 28 && f28 != null)
+            {
+                return await f28(_value28);
+            }
+            if (_index == 29 && f29 != null)
+            {
+                return await f29(_value29);
+            }
+            if (_index == 30 && f30 != null)
+            {
+                return await f30(_value30);
+            }
+            if (_index == 31 && f31 != null)
+            {
+                return await f31(_value31);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> FromT2(T2 input) => input;
@@ -642,8 +947,1403 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> FromT30(T30 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> FromT31(T31 input) => input;
 
-        
-        public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT0<TResult>(Func<T0, TResult> mapFunc)
+        
+        public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT0<TResult>(Func<T0, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT2<TResult>(Func<T2, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT4<TResult>(Func<T4, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT6<TResult>(Func<T6, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT8<TResult>(Func<T8, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT10<TResult>(Func<T10, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT10Async<TResult>(Func<T10, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => await mapFunc(AsT10),
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT11Async<TResult>(Func<T11, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => await mapFunc(AsT11),
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT12<TResult>(Func<T12, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT12Async<TResult>(Func<T12, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => await mapFunc(AsT12),
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT13Async<TResult>(Func<T13, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => await mapFunc(AsT13),
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT14<TResult>(Func<T14, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => mapFunc(AsT14),
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT14Async<TResult>(Func<T14, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => await mapFunc(AsT14),
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+            
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => mapFunc(AsT15),
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => AsT31,
+                _ => throw new InvalidOperationException()
+            };
+        }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT15Async<TResult>(Func<T15, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -651,7 +2351,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             }
             return _index switch
             {
-                0 => mapFunc(AsT0),
+                0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
@@ -666,7 +2366,7 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => AsT15,
+                15 => await mapFunc(AsT15),
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -686,8 +2386,9 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT1<TResult>(Func<T1, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT16<TResult>(Func<T16, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -696,7 +2397,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             return _index switch
             {
                 0 => AsT0,
-                1 => mapFunc(AsT1),
+                1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
@@ -711,7 +2412,7 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -730,8 +2431,9 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT2<TResult>(Func<T2, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT16Async<TResult>(Func<T16, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -741,7 +2443,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
             {
                 0 => AsT0,
                 1 => AsT1,
-                2 => mapFunc(AsT2),
+                2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
@@ -755,7 +2457,7 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => AsT16,
+                16 => await mapFunc(AsT16),
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
@@ -774,8 +2476,9 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT3<TResult>(Func<T3, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT17<TResult>(Func<T17, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -786,7 +2489,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 0 => AsT0,
                 1 => AsT1,
                 2 => AsT2,
-                3 => mapFunc(AsT3),
+                3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
@@ -800,7 +2503,7 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -818,8 +2521,9 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT4<TResult>(Func<T4, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT17Async<TResult>(Func<T17, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -831,7 +2535,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 1 => AsT1,
                 2 => AsT2,
                 3 => AsT3,
-                4 => mapFunc(AsT4),
+                4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
@@ -844,7 +2548,7 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => AsT17,
+                17 => await mapFunc(AsT17),
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
@@ -862,8 +2566,9 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT5<TResult>(Func<T5, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT18<TResult>(Func<T18, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -876,7 +2581,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 2 => AsT2,
                 3 => AsT3,
                 4 => AsT4,
-                5 => mapFunc(AsT5),
+                5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
@@ -889,7 +2594,7 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -906,8 +2611,9 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT6<TResult>(Func<T6, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT18Async<TResult>(Func<T18, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -921,7 +2627,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 3 => AsT3,
                 4 => AsT4,
                 5 => AsT5,
-                6 => mapFunc(AsT6),
+                6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
@@ -933,7 +2639,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => AsT18,
+                18 => await mapFunc(AsT18),
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
@@ -950,8 +2656,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT7<TResult>(Func<T7, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT19<TResult>(Func<T19, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -966,7 +2673,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 4 => AsT4,
                 5 => AsT5,
                 6 => AsT6,
-                7 => mapFunc(AsT7),
+                7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
@@ -978,7 +2685,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -994,8 +2701,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT8<TResult>(Func<T8, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT19Async<TResult>(Func<T19, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1011,7 +2719,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 5 => AsT5,
                 6 => AsT6,
                 7 => AsT7,
-                8 => mapFunc(AsT8),
+                8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
@@ -1022,7 +2730,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => AsT19,
+                19 => await mapFunc(AsT19),
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
@@ -1038,8 +2746,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT9<TResult>(Func<T9, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT20<TResult>(Func<T20, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1056,7 +2765,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 6 => AsT6,
                 7 => AsT7,
                 8 => AsT8,
-                9 => mapFunc(AsT9),
+                9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
@@ -1067,7 +2776,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1082,8 +2791,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult, T10, T11, T12, T13, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT10<TResult>(Func<T10, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT20Async<TResult>(Func<T20, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1101,7 +2811,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 7 => AsT7,
                 8 => AsT8,
                 9 => AsT9,
-                10 => mapFunc(AsT10),
+                10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
@@ -1111,7 +2821,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => AsT20,
+                20 => await mapFunc(AsT20),
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
@@ -1126,8 +2836,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult, T11, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT11<TResult>(Func<T11, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT21<TResult>(Func<T21, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1146,7 +2857,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 8 => AsT8,
                 9 => AsT9,
                 10 => AsT10,
-                11 => mapFunc(AsT11),
+                11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
@@ -1156,7 +2867,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => AsT21,
+                21 => mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1170,8 +2881,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult, T12, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT12<TResult>(Func<T12, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT21Async<TResult>(Func<T21, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1191,7 +2903,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 9 => AsT9,
                 10 => AsT10,
                 11 => AsT11,
-                12 => mapFunc(AsT12),
+                12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
@@ -1200,7 +2912,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => AsT21,
+                21 => await mapFunc(AsT21),
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
@@ -1214,8 +2926,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TResult, T13, T14
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT13<TResult>(Func<T13, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT22<TResult>(Func<T22, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1236,7 +2949,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 10 => AsT10,
                 11 => AsT11,
                 12 => AsT12,
-                13 => mapFunc(AsT13),
+                13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
@@ -1245,7 +2958,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => AsT22,
+                22 => mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
@@ -1258,8 +2971,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TResult, T14
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT14<TResult>(Func<T14, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27, T28, T29, T30, T31>> MapT22Async<TResult>(Func<T22, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1281,7 +2995,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 11 => AsT11,
                 12 => AsT12,
                 13 => AsT13,
-                14 => mapFunc(AsT14),
+                14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
@@ -1289,7 +3003,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => AsT22,
+                22 => await mapFunc(AsT22),
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
@@ -1302,8 +3016,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, TResult
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TResult, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT15<TResult>(Func<T15, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27, T28, T29, T30, T31> MapT23<TResult>(Func<T23, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1326,7 +3041,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 12 => AsT12,
                 13 => AsT13,
                 14 => AsT14,
-                15 => mapFunc(AsT15),
+                15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
@@ -1334,7 +3049,7 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => AsT23,
+                23 => mapFunc(AsT23),
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
@@ -1346,8 +3061,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, TR
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT16<TResult>(Func<T16, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27, T28, T29, T30, T31>> MapT23Async<TResult>(Func<T23, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1371,14 +3087,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 13 => AsT13,
                 14 => AsT14,
                 15 => AsT15,
-                16 => mapFunc(AsT16),
+                16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => AsT23,
+                23 => await mapFunc(AsT23),
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
@@ -1390,8 +3106,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, TResult, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT17<TResult>(Func<T17, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27, T28, T29, T30, T31> MapT24<TResult>(Func<T24, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1416,14 +3133,14 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 14 => AsT14,
                 15 => AsT15,
                 16 => AsT16,
-                17 => mapFunc(AsT17),
+                17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
-                24 => AsT24,
+                24 => mapFunc(AsT24),
                 25 => AsT25,
                 26 => AsT26,
                 27 => AsT27,
@@ -1434,8 +3151,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, TResult, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT18<TResult>(Func<T18, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27, T28, T29, T30, T31>> MapT24Async<TResult>(Func<T24, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1461,13 +3179,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 15 => AsT15,
                 16 => AsT16,
                 17 => AsT17,
-                18 => mapFunc(AsT18),
+                18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
-                24 => AsT24,
+                24 => await mapFunc(AsT24),
                 25 => AsT25,
                 26 => AsT26,
                 27 => AsT27,
@@ -1478,8 +3196,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, TResult, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT19<TResult>(Func<T19, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27, T28, T29, T30, T31> MapT25<TResult>(Func<T25, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1506,13 +3225,13 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 16 => AsT16,
                 17 => AsT17,
                 18 => AsT18,
-                19 => mapFunc(AsT19),
+                19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
-                25 => AsT25,
+                25 => mapFunc(AsT25),
                 26 => AsT26,
                 27 => AsT27,
                 28 => AsT28,
@@ -1522,8 +3241,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, TResult, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT20<TResult>(Func<T20, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27, T28, T29, T30, T31>> MapT25Async<TResult>(Func<T25, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1551,12 +3271,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 17 => AsT17,
                 18 => AsT18,
                 19 => AsT19,
-                20 => mapFunc(AsT20),
+                20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
-                25 => AsT25,
+                25 => await mapFunc(AsT25),
                 26 => AsT26,
                 27 => AsT27,
                 28 => AsT28,
@@ -1566,8 +3286,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, TResult, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT21<TResult>(Func<T21, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27, T28, T29, T30, T31> MapT26<TResult>(Func<T26, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1596,12 +3317,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 18 => AsT18,
                 19 => AsT19,
                 20 => AsT20,
-                21 => mapFunc(AsT21),
+                21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
-                26 => AsT26,
+                26 => mapFunc(AsT26),
                 27 => AsT27,
                 28 => AsT28,
                 29 => AsT29,
@@ -1610,8 +3331,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, TResult, T23, T24, T25, T26, T27, T28, T29, T30, T31> MapT22<TResult>(Func<T22, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27, T28, T29, T30, T31>> MapT26Async<TResult>(Func<T26, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1641,11 +3363,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 19 => AsT19,
                 20 => AsT20,
                 21 => AsT21,
-                22 => mapFunc(AsT22),
+                22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
-                26 => AsT26,
+                26 => await mapFunc(AsT26),
                 27 => AsT27,
                 28 => AsT28,
                 29 => AsT29,
@@ -1654,8 +3376,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, TResult, T24, T25, T26, T27, T28, T29, T30, T31> MapT23<TResult>(Func<T23, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, TResult, T28, T29, T30, T31> MapT27<TResult>(Func<T27, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1686,11 +3409,11 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 20 => AsT20,
                 21 => AsT21,
                 22 => AsT22,
-                23 => mapFunc(AsT23),
+                23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
-                27 => AsT27,
+                27 => mapFunc(AsT27),
                 28 => AsT28,
                 29 => AsT29,
                 30 => AsT30,
@@ -1698,8 +3421,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, TResult, T25, T26, T27, T28, T29, T30, T31> MapT24<TResult>(Func<T24, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, TResult, T28, T29, T30, T31>> MapT27Async<TResult>(Func<T27, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1731,10 +3455,10 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 21 => AsT21,
                 22 => AsT22,
                 23 => AsT23,
-                24 => mapFunc(AsT24),
+                24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
-                27 => AsT27,
+                27 => await mapFunc(AsT27),
                 28 => AsT28,
                 29 => AsT29,
                 30 => AsT30,
@@ -1742,8 +3466,9 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, TResult, T26, T27, T28, T29, T30, T31> MapT25<TResult>(Func<T25, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, TResult, T29, T30, T31> MapT28<TResult>(Func<T28, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1776,18 +3501,19 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 22 => AsT22,
                 23 => AsT23,
                 24 => AsT24,
-                25 => mapFunc(AsT25),
+                25 => AsT25,
                 26 => AsT26,
                 27 => AsT27,
-                28 => AsT28,
+                28 => mapFunc(AsT28),
                 29 => AsT29,
                 30 => AsT30,
                 31 => AsT31,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, TResult, T27, T28, T29, T30, T31> MapT26<TResult>(Func<T26, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, TResult, T29, T30, T31>> MapT28Async<TResult>(Func<T28, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1821,17 +3547,18 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 23 => AsT23,
                 24 => AsT24,
                 25 => AsT25,
-                26 => mapFunc(AsT26),
+                26 => AsT26,
                 27 => AsT27,
-                28 => AsT28,
+                28 => await mapFunc(AsT28),
                 29 => AsT29,
                 30 => AsT30,
                 31 => AsT31,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, TResult, T28, T29, T30, T31> MapT27<TResult>(Func<T27, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, TResult, T30, T31> MapT29<TResult>(Func<T29, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1866,16 +3593,17 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 24 => AsT24,
                 25 => AsT25,
                 26 => AsT26,
-                27 => mapFunc(AsT27),
+                27 => AsT27,
                 28 => AsT28,
-                29 => AsT29,
+                29 => mapFunc(AsT29),
                 30 => AsT30,
                 31 => AsT31,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, TResult, T29, T30, T31> MapT28<TResult>(Func<T28, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, TResult, T30, T31>> MapT29Async<TResult>(Func<T29, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1911,15 +3639,16 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 25 => AsT25,
                 26 => AsT26,
                 27 => AsT27,
-                28 => mapFunc(AsT28),
-                29 => AsT29,
+                28 => AsT28,
+                29 => await mapFunc(AsT29),
                 30 => AsT30,
                 31 => AsT31,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, TResult, T30, T31> MapT29<TResult>(Func<T29, TResult> mapFunc)
+        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, TResult, T31> MapT30<TResult>(Func<T30, TResult> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -1956,14 +3685,15 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 26 => AsT26,
                 27 => AsT27,
                 28 => AsT28,
-                29 => mapFunc(AsT29),
-                30 => AsT30,
+                29 => AsT29,
+                30 => mapFunc(AsT30),
                 31 => AsT31,
                 _ => throw new InvalidOperationException()
             };
         }
-            
-        public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, TResult, T31> MapT30<TResult>(Func<T30, TResult> mapFunc)
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, TResult, T31>> MapT30Async<TResult>(Func<T30, Task<TResult>> mapFunc)
         {
             if (mapFunc == null)
             {
@@ -2001,11 +3731,12 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
                 27 => AsT27,
                 28 => AsT28,
                 29 => AsT29,
-                30 => mapFunc(AsT30),
+                30 => await mapFunc(AsT30),
                 31 => AsT31,
                 _ => throw new InvalidOperationException()
             };
         }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, TResult> MapT31<TResult>(Func<T31, TResult> mapFunc)
         {
@@ -2051,6 +3782,52 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, TResult>> MapT31Async<TResult>(Func<T31, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                10 => AsT10,
+                11 => AsT11,
+                12 => AsT12,
+                13 => AsT13,
+                14 => AsT14,
+                15 => AsT15,
+                16 => AsT16,
+                17 => AsT17,
+                18 => AsT18,
+                19 => AsT19,
+                20 => AsT20,
+                21 => AsT21,
+                22 => AsT22,
+                23 => AsT23,
+                24 => AsT24,
+                25 => AsT25,
+                26 => AsT26,
+                27 => AsT27,
+                28 => AsT28,
+                29 => AsT29,
+                30 => AsT30,
+                31 => await mapFunc(AsT31),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, T23, T24, T25, T26, T27, T28, T29, T30, T31> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Extended/OneOfT9.generated.cs b/OneOf.Extended/OneOfT9.generated.cs
index a1efcd2..a76cbba 100644
--- a/OneOf.Extended/OneOfT9.generated.cs
+++ b/OneOf.Extended/OneOfT9.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -168,6 +171,63 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8, Func<T9,Task> f9)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            if (_index == 9 && f9 != null)
+            {
+                await f9(_value9);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8, Func<T9, TResult> f9)
         {
             if (_index == 0 && f0 != null)
@@ -213,6 +273,53 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8, Func<T9, Task<TResult>> f9)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            if (_index == 9 && f9 != null)
+            {
+                return await f9(_value9);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9> FromT2(T2 input) => input;
@@ -246,6 +353,30 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9> MapT0<TResult>(Func<T0
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8, T9>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -268,6 +399,30 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9> MapT1<TResult>(Func<T1
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8, T9>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -290,6 +445,30 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9> MapT2<TResult>(Func<T2
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8, T9>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
@@ -312,6 +491,30 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9> MapT3<TResult>(Func<T3
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8, T9>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
@@ -334,6 +537,30 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9> MapT4<TResult>(Func<T4
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8, T9>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
@@ -356,6 +583,30 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9> MapT5<TResult>(Func<T5
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8, T9>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
@@ -378,6 +629,30 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9> MapT6<TResult>(Func<T6
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8, T9>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                9 => AsT9,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
@@ -400,6 +675,30 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9> MapT7<TResult>(Func<T7
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8, T9>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                9 => AsT9,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9> MapT8<TResult>(Func<T8, TResult> mapFunc)
         {
@@ -422,6 +721,30 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9> MapT8<TResult>(Func<T8
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult, T9>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                9 => AsT9,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult> MapT9<TResult>(Func<T9, TResult> mapFunc)
         {
@@ -445,6 +768,30 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult> MapT9<TResult>(Func<T9
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8, TResult>> MapT9Async<TResult>(Func<T9, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                9 => await mapFunc(AsT9),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8, T9> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf.Tests/MapTests.cs b/OneOf.Tests/MapTests.cs
index 45dbfa8..96edb24 100644
--- a/OneOf.Tests/MapTests.cs
+++ b/OneOf.Tests/MapTests.cs
@@ -1,4 +1,6 @@
-using System.Globalization;
+using System;
+using System.Globalization;
+using System.Threading.Tasks;
 using NUnit.Framework;
 using OneOf;
 
@@ -14,10 +16,34 @@ public void MapValue()
             var resolveString = ResolveString("6");
         }
 
+        [Test]
+        [TestCase(2.1, ExpectedResult = "2.1")]
+        [TestCase(4, ExpectedResult = "4")]
+        [TestCase("6", ExpectedResult = "6")]
+        public async Task<string> MapValueAsync<T>(T value) 
+        {
+            OneOf<double, int, string> oneOf = value switch
+            {
+                double v => v,
+                int v => v,
+                string v => v,
+                _ => throw new InvalidOperationException("Invalid value type for this OneOf type")
+            };
+            
+            return await ResolveStringAsync(oneOf);
+        }
+
         private string ResolveString(OneOf<double, int, string> input)
             => input
                 .MapT0(d => d.ToString(CultureInfo.InvariantCulture))
                 .MapT1(i => i.ToString(CultureInfo.InvariantCulture))
                 .Match(t1 => t1, t2 => t2, t3 => t3);
+
+        private async Task<string> ResolveStringAsync(OneOf<double, int, string> input)
+        {
+            var map1 = await input.MapT0Async(d => Task.FromResult(d.ToString(CultureInfo.InvariantCulture)));
+            var map2 = await map1.MapT1Async(i => Task.FromResult(i.ToString(CultureInfo.InvariantCulture)));
+            return await map2.MatchAsync(t1 => Task.FromResult(t1), t2 => Task.FromResult(t2), t3 => Task.FromResult(t3));
+        }
     }
 }
diff --git a/OneOf.Tests/OneOf.Tests.csproj b/OneOf.Tests/OneOf.Tests.csproj
index 4598ccc..c4e4560 100644
--- a/OneOf.Tests/OneOf.Tests.csproj
+++ b/OneOf.Tests/OneOf.Tests.csproj
@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>net451</TargetFramework>
+    <LangVersion>9.0</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
@@ -14,4 +15,5 @@
   <ItemGroup>
     <ProjectReference Include="..\OneOf\OneOf.csproj" />
   </ItemGroup>
+  
 </Project>
\ No newline at end of file
diff --git a/OneOf/OneOfBaseT0.generated.cs b/OneOf/OneOfBaseT0.generated.cs
index 52a7fba..80dfba3 100644
--- a/OneOf/OneOfBaseT0.generated.cs
+++ b/OneOf/OneOfBaseT0.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -46,6 +49,18 @@ public void Switch(Action<T0> f0)
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0)
         {
             if (_index == 0 && f0 != null)
@@ -55,6 +70,17 @@ public TResult Match<TResult>(Func<T0, TResult> f0)
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf/OneOfBaseT1.generated.cs b/OneOf/OneOfBaseT1.generated.cs
index b5816b4..d4cd6ae 100644
--- a/OneOf/OneOfBaseT1.generated.cs
+++ b/OneOf/OneOfBaseT1.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -59,6 +62,23 @@ public void Switch(Action<T0> f0, Action<T1> f1)
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1)
         {
             if (_index == 0 && f0 != null)
@@ -72,6 +92,21 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1)
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf/OneOfBaseT2.generated.cs b/OneOf/OneOfBaseT2.generated.cs
index d8ed1a8..434c3ed 100644
--- a/OneOf/OneOfBaseT2.generated.cs
+++ b/OneOf/OneOfBaseT2.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -72,6 +75,28 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2)
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2)
         {
             if (_index == 0 && f0 != null)
@@ -89,6 +114,25 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf/OneOfBaseT3.generated.cs b/OneOf/OneOfBaseT3.generated.cs
index c47bd8e..d39c3e9 100644
--- a/OneOf/OneOfBaseT3.generated.cs
+++ b/OneOf/OneOfBaseT3.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -85,6 +88,33 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3)
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3)
         {
             if (_index == 0 && f0 != null)
@@ -106,6 +136,29 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf/OneOfBaseT4.generated.cs b/OneOf/OneOfBaseT4.generated.cs
index 454c6cf..55e737d 100644
--- a/OneOf/OneOfBaseT4.generated.cs
+++ b/OneOf/OneOfBaseT4.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -98,6 +101,38 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4)
         {
             if (_index == 0 && f0 != null)
@@ -123,6 +158,33 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf/OneOfBaseT5.generated.cs b/OneOf/OneOfBaseT5.generated.cs
index feb72c3..5732bc9 100644
--- a/OneOf/OneOfBaseT5.generated.cs
+++ b/OneOf/OneOfBaseT5.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -111,6 +114,43 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5)
         {
             if (_index == 0 && f0 != null)
@@ -140,6 +180,37 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf/OneOfBaseT6.generated.cs b/OneOf/OneOfBaseT6.generated.cs
index 607b865..c1fe8c6 100644
--- a/OneOf/OneOfBaseT6.generated.cs
+++ b/OneOf/OneOfBaseT6.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -124,6 +127,48 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6)
         {
             if (_index == 0 && f0 != null)
@@ -157,6 +202,41 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf/OneOfBaseT7.generated.cs b/OneOf/OneOfBaseT7.generated.cs
index c30d6bf..4a2624f 100644
--- a/OneOf/OneOfBaseT7.generated.cs
+++ b/OneOf/OneOfBaseT7.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -137,6 +140,53 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7)
         {
             if (_index == 0 && f0 != null)
@@ -174,6 +224,45 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf/OneOfBaseT8.generated.cs b/OneOf/OneOfBaseT8.generated.cs
index 5ee8beb..2dc8392 100644
--- a/OneOf/OneOfBaseT8.generated.cs
+++ b/OneOf/OneOfBaseT8.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -150,6 +153,58 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8)
         {
             if (_index == 0 && f0 != null)
@@ -191,6 +246,49 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         
 
         
diff --git a/OneOf/OneOfT0.generated.cs b/OneOf/OneOfT0.generated.cs
index 1f3090b..d116e6f 100644
--- a/OneOf/OneOfT0.generated.cs
+++ b/OneOf/OneOfT0.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -42,6 +45,18 @@ public void Switch(Action<T0> f0)
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0)
         {
             if (_index == 0 && f0 != null)
@@ -51,6 +66,17 @@ public TResult Match<TResult>(Func<T0, TResult> f0)
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0> FromT0(T0 input) => input;
 
         
@@ -67,6 +93,21 @@ public OneOf<TResult> MapT0<TResult>(Func<T0, TResult> mapFunc)
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
         bool Equals(OneOf<T0> other) =>
             _index == other._index &&
             _index switch
diff --git a/OneOf/OneOfT1.generated.cs b/OneOf/OneOfT1.generated.cs
index e6b645c..9e59883 100644
--- a/OneOf/OneOfT1.generated.cs
+++ b/OneOf/OneOfT1.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -56,6 +59,23 @@ public void Switch(Action<T0> f0, Action<T1> f1)
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1)
         {
             if (_index == 0 && f0 != null)
@@ -69,6 +89,21 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1)
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1> FromT0(T0 input) => input;
         public static OneOf<T0, T1> FromT1(T1 input) => input;
 
@@ -86,6 +121,22 @@ public OneOf<TResult, T1> MapT0<TResult>(Func<T0, TResult> mapFunc)
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -101,6 +152,22 @@ public OneOf<T0, TResult> MapT1<TResult>(Func<T1, TResult> mapFunc)
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out T1 remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf/OneOfT2.generated.cs b/OneOf/OneOfT2.generated.cs
index 9e4e68c..95a01f2 100644
--- a/OneOf/OneOfT2.generated.cs
+++ b/OneOf/OneOfT2.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -70,6 +73,28 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2)
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2)
         {
             if (_index == 0 && f0 != null)
@@ -87,6 +112,25 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2> FromT2(T2 input) => input;
@@ -106,6 +150,23 @@ public OneOf<TResult, T1, T2> MapT0<TResult>(Func<T0, TResult> mapFunc)
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -121,6 +182,23 @@ public OneOf<T0, TResult, T2> MapT1<TResult>(Func<T1, TResult> mapFunc)
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -137,6 +215,23 @@ public OneOf<T0, T1, TResult> MapT2<TResult>(Func<T2, TResult> mapFunc)
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf/OneOfT3.generated.cs b/OneOf/OneOfT3.generated.cs
index b6556fc..07a8036 100644
--- a/OneOf/OneOfT3.generated.cs
+++ b/OneOf/OneOfT3.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -84,6 +87,33 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3)
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3)
         {
             if (_index == 0 && f0 != null)
@@ -105,6 +135,29 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3> FromT2(T2 input) => input;
@@ -126,6 +179,24 @@ public OneOf<TResult, T1, T2, T3> MapT0<TResult>(Func<T0, TResult> mapFunc)
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -142,6 +213,24 @@ public OneOf<T0, TResult, T2, T3> MapT1<TResult>(Func<T1, TResult> mapFunc)
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult, T3> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -158,6 +247,24 @@ public OneOf<T0, T1, TResult, T3> MapT2<TResult>(Func<T2, TResult> mapFunc)
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, TResult> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
@@ -175,6 +282,24 @@ public OneOf<T0, T1, T2, TResult> MapT3<TResult>(Func<T3, TResult> mapFunc)
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf/OneOfT4.generated.cs b/OneOf/OneOfT4.generated.cs
index 38245fb..26762d7 100644
--- a/OneOf/OneOfT4.generated.cs
+++ b/OneOf/OneOfT4.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -98,6 +101,38 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4)
         {
             if (_index == 0 && f0 != null)
@@ -123,6 +158,33 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4> FromT2(T2 input) => input;
@@ -146,6 +208,25 @@ public OneOf<TResult, T1, T2, T3, T4> MapT0<TResult>(Func<T0, TResult> mapFunc)
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -163,6 +244,25 @@ public OneOf<T0, TResult, T2, T3, T4> MapT1<TResult>(Func<T1, TResult> mapFunc)
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult, T3, T4> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -180,6 +280,25 @@ public OneOf<T0, T1, TResult, T3, T4> MapT2<TResult>(Func<T2, TResult> mapFunc)
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, TResult, T4> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
@@ -197,6 +316,25 @@ public OneOf<T0, T1, T2, TResult, T4> MapT3<TResult>(Func<T3, TResult> mapFunc)
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, TResult> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
@@ -215,6 +353,25 @@ public OneOf<T0, T1, T2, T3, TResult> MapT4<TResult>(Func<T4, TResult> mapFunc)
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf/OneOfT5.generated.cs b/OneOf/OneOfT5.generated.cs
index 83ac23e..b9a71b3 100644
--- a/OneOf/OneOfT5.generated.cs
+++ b/OneOf/OneOfT5.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -112,6 +115,43 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5)
         {
             if (_index == 0 && f0 != null)
@@ -141,6 +181,37 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5> FromT2(T2 input) => input;
@@ -166,6 +237,26 @@ public OneOf<TResult, T1, T2, T3, T4, T5> MapT0<TResult>(Func<T0, TResult> mapFu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4, T5> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -184,6 +275,26 @@ public OneOf<T0, TResult, T2, T3, T4, T5> MapT1<TResult>(Func<T1, TResult> mapFu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult, T3, T4, T5> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -202,6 +313,26 @@ public OneOf<T0, T1, TResult, T3, T4, T5> MapT2<TResult>(Func<T2, TResult> mapFu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, TResult, T4, T5> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
@@ -220,6 +351,26 @@ public OneOf<T0, T1, T2, TResult, T4, T5> MapT3<TResult>(Func<T3, TResult> mapFu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, TResult, T5> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
@@ -238,6 +389,26 @@ public OneOf<T0, T1, T2, T3, TResult, T5> MapT4<TResult>(Func<T4, TResult> mapFu
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, TResult> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
@@ -257,6 +428,26 @@ public OneOf<T0, T1, T2, T3, T4, TResult> MapT5<TResult>(Func<T5, TResult> mapFu
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf/OneOfT6.generated.cs b/OneOf/OneOfT6.generated.cs
index 9922c8a..07f7005 100644
--- a/OneOf/OneOfT6.generated.cs
+++ b/OneOf/OneOfT6.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -126,6 +129,48 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6)
         {
             if (_index == 0 && f0 != null)
@@ -159,6 +204,41 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6> FromT2(T2 input) => input;
@@ -186,6 +266,27 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6> MapT0<TResult>(Func<T0, TResult> m
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4, T5, T6> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -205,6 +306,27 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6> MapT1<TResult>(Func<T1, TResult> m
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult, T3, T4, T5, T6> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -224,6 +346,27 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6> MapT2<TResult>(Func<T2, TResult> m
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, TResult, T4, T5, T6> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
@@ -243,6 +386,27 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6> MapT3<TResult>(Func<T3, TResult> m
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, TResult, T5, T6> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
@@ -262,6 +426,27 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6> MapT4<TResult>(Func<T4, TResult> m
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, TResult, T6> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
@@ -281,6 +466,27 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6> MapT5<TResult>(Func<T5, TResult> m
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, TResult> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
@@ -301,6 +507,27 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult> MapT6<TResult>(Func<T6, TResult> m
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf/OneOfT7.generated.cs b/OneOf/OneOfT7.generated.cs
index c0b0160..311ee4a 100644
--- a/OneOf/OneOfT7.generated.cs
+++ b/OneOf/OneOfT7.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -140,6 +143,53 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7)
         {
             if (_index == 0 && f0 != null)
@@ -177,6 +227,45 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7> FromT2(T2 input) => input;
@@ -206,6 +295,28 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7> MapT0<TResult>(Func<T0, TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -226,6 +337,28 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7> MapT1<TResult>(Func<T1, TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -246,6 +379,28 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7> MapT2<TResult>(Func<T2, TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
@@ -266,6 +421,28 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7> MapT3<TResult>(Func<T3, TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
@@ -286,6 +463,28 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7> MapT4<TResult>(Func<T4, TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
@@ -306,6 +505,28 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7> MapT5<TResult>(Func<T5, TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
@@ -326,6 +547,28 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7> MapT6<TResult>(Func<T6, TResul
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
@@ -347,6 +590,28 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult> MapT7<TResult>(Func<T7, TResul
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7> remainder)
 		{
 			value = IsT0 ? AsT0 : default;
diff --git a/OneOf/OneOfT8.generated.cs b/OneOf/OneOfT8.generated.cs
index e040095..5cb57e9 100644
--- a/OneOf/OneOfT8.generated.cs
+++ b/OneOf/OneOfT8.generated.cs
@@ -1,5 +1,8 @@
 using System;
 using static OneOf.Functions;
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+using System.Threading.Tasks;
+#endif
 
 namespace OneOf
 {
@@ -154,6 +157,58 @@ public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2, Action<T3> f3, A
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task SwitchAsync(Func<T0,Task> f0, Func<T1,Task> f1, Func<T2,Task> f2, Func<T3,Task> f3, Func<T4,Task> f4, Func<T5,Task> f5, Func<T6,Task> f6, Func<T7,Task> f7, Func<T8,Task> f8)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                await f0(_value0);
+                return;
+            }
+            if (_index == 1 && f1 != null)
+            {
+                await f1(_value1);
+                return;
+            }
+            if (_index == 2 && f2 != null)
+            {
+                await f2(_value2);
+                return;
+            }
+            if (_index == 3 && f3 != null)
+            {
+                await f3(_value3);
+                return;
+            }
+            if (_index == 4 && f4 != null)
+            {
+                await f4(_value4);
+                return;
+            }
+            if (_index == 5 && f5 != null)
+            {
+                await f5(_value5);
+                return;
+            }
+            if (_index == 6 && f6 != null)
+            {
+                await f6(_value6);
+                return;
+            }
+            if (_index == 7 && f7 != null)
+            {
+                await f7(_value7);
+                return;
+            }
+            if (_index == 8 && f8 != null)
+            {
+                await f8(_value8);
+                return;
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2, Func<T3, TResult> f3, Func<T4, TResult> f4, Func<T5, TResult> f5, Func<T6, TResult> f6, Func<T7, TResult> f7, Func<T8, TResult> f8)
         {
             if (_index == 0 && f0 != null)
@@ -195,6 +250,49 @@ public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T
             throw new InvalidOperationException();
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<TResult> MatchAsync<TResult>(Func<T0, Task<TResult>> f0, Func<T1, Task<TResult>> f1, Func<T2, Task<TResult>> f2, Func<T3, Task<TResult>> f3, Func<T4, Task<TResult>> f4, Func<T5, Task<TResult>> f5, Func<T6, Task<TResult>> f6, Func<T7, Task<TResult>> f7, Func<T8, Task<TResult>> f8)
+        {
+            if (_index == 0 && f0 != null)
+            {
+                return await f0(_value0);
+            }
+            if (_index == 1 && f1 != null)
+            {
+                return await f1(_value1);
+            }
+            if (_index == 2 && f2 != null)
+            {
+                return await f2(_value2);
+            }
+            if (_index == 3 && f3 != null)
+            {
+                return await f3(_value3);
+            }
+            if (_index == 4 && f4 != null)
+            {
+                return await f4(_value4);
+            }
+            if (_index == 5 && f5 != null)
+            {
+                return await f5(_value5);
+            }
+            if (_index == 6 && f6 != null)
+            {
+                return await f6(_value6);
+            }
+            if (_index == 7 && f7 != null)
+            {
+                return await f7(_value7);
+            }
+            if (_index == 8 && f8 != null)
+            {
+                return await f8(_value8);
+            }
+            throw new InvalidOperationException();
+        }
+#endif
+
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8> FromT0(T0 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8> FromT1(T1 input) => input;
         public static OneOf<T0, T1, T2, T3, T4, T5, T6, T7, T8> FromT2(T2 input) => input;
@@ -226,6 +324,29 @@ public OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8> MapT0<TResult>(Func<T0, TR
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<TResult, T1, T2, T3, T4, T5, T6, T7, T8>> MapT0Async<TResult>(Func<T0, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => await mapFunc(AsT0),
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8> MapT1<TResult>(Func<T1, TResult> mapFunc)
         {
@@ -247,6 +368,29 @@ public OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8> MapT1<TResult>(Func<T1, TR
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, TResult, T2, T3, T4, T5, T6, T7, T8>> MapT1Async<TResult>(Func<T1, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => await mapFunc(AsT1),
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8> MapT2<TResult>(Func<T2, TResult> mapFunc)
         {
@@ -268,6 +412,29 @@ public OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8> MapT2<TResult>(Func<T2, TR
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, TResult, T3, T4, T5, T6, T7, T8>> MapT2Async<TResult>(Func<T2, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => await mapFunc(AsT2),
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8> MapT3<TResult>(Func<T3, TResult> mapFunc)
         {
@@ -289,6 +456,29 @@ public OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8> MapT3<TResult>(Func<T3, TR
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, TResult, T4, T5, T6, T7, T8>> MapT3Async<TResult>(Func<T3, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => await mapFunc(AsT3),
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8> MapT4<TResult>(Func<T4, TResult> mapFunc)
         {
@@ -310,6 +500,29 @@ public OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8> MapT4<TResult>(Func<T4, TR
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, TResult, T5, T6, T7, T8>> MapT4Async<TResult>(Func<T4, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => await mapFunc(AsT4),
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8> MapT5<TResult>(Func<T5, TResult> mapFunc)
         {
@@ -331,6 +544,29 @@ public OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8> MapT5<TResult>(Func<T5, TR
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, TResult, T6, T7, T8>> MapT5Async<TResult>(Func<T5, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => await mapFunc(AsT5),
+                6 => AsT6,
+                7 => AsT7,
+                8 => AsT8,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8> MapT6<TResult>(Func<T6, TResult> mapFunc)
         {
@@ -352,6 +588,29 @@ public OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8> MapT6<TResult>(Func<T6, TR
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, TResult, T7, T8>> MapT6Async<TResult>(Func<T6, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => await mapFunc(AsT6),
+                7 => AsT7,
+                8 => AsT8,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8> MapT7<TResult>(Func<T7, TResult> mapFunc)
         {
@@ -373,6 +632,29 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8> MapT7<TResult>(Func<T7, TR
                 _ => throw new InvalidOperationException()
             };
         }
+
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, TResult, T8>> MapT7Async<TResult>(Func<T7, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => await mapFunc(AsT7),
+                8 => AsT8,
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
             
         public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult> MapT8<TResult>(Func<T8, TResult> mapFunc)
         {
@@ -395,6 +677,29 @@ public OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult> MapT8<TResult>(Func<T8, TR
             };
         }
 
+#if NETSTANDARD2_0 || NET40_OR_GREATER
+        public async Task<OneOf<T0, T1, T2, T3, T4, T5, T6, T7, TResult>> MapT8Async<TResult>(Func<T8, Task<TResult>> mapFunc)
+        {
+            if (mapFunc == null)
+            {
+                throw new ArgumentNullException(nameof(mapFunc));
+            }
+            return _index switch
+            {
+                0 => AsT0,
+                1 => AsT1,
+                2 => AsT2,
+                3 => AsT3,
+                4 => AsT4,
+                5 => AsT5,
+                6 => AsT6,
+                7 => AsT7,
+                8 => await mapFunc(AsT8),
+                _ => throw new InvalidOperationException()
+            };
+        }
+#endif
+
 		public bool TryPickT0(out T0 value, out OneOf<T1, T2, T3, T4, T5, T6, T7, T8> remainder)
 		{
 			value = IsT0 ? AsT0 : default;