Added ?Sized as requirement for reader parameter of poll_read_buf function

Author: tglane

tokio-util/src/util/poll_buf.rs

@@ -46,7 +46,7 @@ use std::task::{Context, Poll};
 /// # }
 /// ```
 #[cfg_attr(not(feature = "io"), allow(unreachable_pub))]
-pub fn poll_read_buf<T: AsyncRead, B: BufMut>(
+pub fn poll_read_buf<T: AsyncRead + ?Sized, B: BufMut>(
     io: Pin<&mut T>,
     cx: &mut Context<'_>,
     buf: &mut B,
@@ -143,3 +143,15 @@ pub fn poll_write_buf<T: AsyncWrite, B: Buf>(
 
     Poll::Ready(Ok(n))
 }
+
+#[cfg(test)]
+mod tests {
+
+    fn poll_read(
+        io: &mut (dyn tokio::io::AsyncRead + Unpin),
+        cx: &mut std::task::Context<'_>,
+        buf: &mut impl bytes::BufMut,
+    ) {
+        let _ = super::poll_read_buf(std::pin::Pin::new(io), cx, buf);
+    }
+}