util: upgrade tokio-util to bytes 0.6 (#3052)

tokio/tests/io_read_buf.rs

@@ -4,6 +4,7 @@
 use tokio::io::{AsyncRead, AsyncReadExt, ReadBuf};
 use tokio_test::assert_ok;
 
+use futures::future::poll_fn;
 use std::io;
 use std::pin::Pin;
 use std::task::{Context, Poll};
@@ -34,3 +35,38 @@ async fn read_buf() {
     assert_eq!(n, 11);
     assert_eq!(buf[..], b"hello world"[..]);
 }
+
+#[tokio::test]
+async fn poll_read_buf() {
+    struct Rd {
+        cnt: usize,
+    }
+
+    impl AsyncRead for Rd {
+        fn poll_read(
+            mut self: Pin<&mut Self>,
+            _cx: &mut Context<'_>,
+            buf: &mut ReadBuf<'_>,
+        ) -> Poll<io::Result<()>> {
+            self.cnt += 1;
+            buf.put_slice(b"hello world");
+            Poll::Ready(Ok(()))
+        }
+    }
+
+    let mut buf = vec![];
+    let mut rd = Rd { cnt: 0 };
+
+    let res = tokio::spawn(async move {
+        poll_fn(|cx| {
+            let res = rd.poll_read_buf(&mut buf, cx);
+            assert_eq!(1, rd.cnt);
+            assert_eq!(buf[..], b"hello world"[..]);
+            res
+        })
+        .await
+    })
+    .await;
+
+    assert!(matches!(res, Ok(Ok(11usize))));
+}