diff --git a/tokio-util/src/codec/length_delimited.rs b/tokio-util/src/codec/length_delimited.rs
index e114426c2..dec331c5e 100644
--- a/tokio-util/src/codec/length_delimited.rs
+++ b/tokio-util/src/codec/length_delimited.rs
@@ -603,10 +603,10 @@ impl Decoder for LengthDelimitedCodec {
     }
 }
 
-impl Encoder<Bytes> for LengthDelimitedCodec {
+impl Encoder<&[u8]> for LengthDelimitedCodec {
     type Error = io::Error;
 
-    fn encode(&mut self, data: Bytes, dst: &mut BytesMut) -> Result<(), io::Error> {
+    fn encode(&mut self, data: &[u8], dst: &mut BytesMut) -> Result<(), io::Error> {
         let n = data.len();
 
         if n > self.builder.max_frame_len {
@@ -641,12 +641,20 @@ impl Encoder<Bytes> for LengthDelimitedCodec {
         }
 
         // Write the frame to the buffer
-        dst.extend_from_slice(&data[..]);
+        dst.extend_from_slice(data);
 
         Ok(())
     }
 }
 
+impl Encoder<Bytes> for LengthDelimitedCodec {
+    type Error = io::Error;
+
+    fn encode(&mut self, data: Bytes, dst: &mut BytesMut) -> Result<(), io::Error> {
+        Encoder::<&[u8]>::encode(self, data.as_ref(), dst)
+    }
+}
+
 impl Default for LengthDelimitedCodec {
     fn default() -> Self {
         Self::new()
diff --git a/tokio-util/tests/length_delimited.rs b/tokio-util/tests/length_delimited.rs
index 2ff60d13e..2995b4e82 100644
--- a/tokio-util/tests/length_delimited.rs
+++ b/tokio-util/tests/length_delimited.rs
@@ -70,6 +70,26 @@ macro_rules! assert_done {
     }};
 }
 
+fn poll_ready_bytes<T>(
+    sink: Pin<&mut T>,
+    cx: &mut Context<'_>,
+) -> Poll<Result<(), <T as Sink<Bytes>>::Error>>
+where
+    T: Sink<Bytes>,
+{
+    Sink::<Bytes>::poll_ready(sink, cx)
+}
+
+fn poll_flush_bytes<T>(
+    sink: Pin<&mut T>,
+    cx: &mut Context<'_>,
+) -> Poll<Result<(), <T as Sink<Bytes>>::Error>>
+where
+    T: Sink<Bytes>,
+{
+    Sink::<Bytes>::poll_flush(sink, cx)
+}
+
 #[test]
 fn read_empty_io_yields_nothing() {
     let io = Box::pin(FramedRead::new(mock!(), LengthDelimitedCodec::new()));
@@ -423,9 +443,9 @@ fn write_single_frame_length_adjusted() {
     pin_mut!(io);
 
     task::spawn(()).enter(|cx, _| {
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("abcdefghi")));
-        assert_ready_ok!(io.as_mut().poll_flush(cx));
+        assert_ready_ok!(poll_flush_bytes(io.as_mut(), cx));
         assert!(io.get_ref().calls.is_empty());
     });
 }
@@ -436,7 +456,7 @@ fn write_nothing_yields_nothing() {
     pin_mut!(io);
 
     task::spawn(()).enter(|cx, _| {
-        assert_ready_ok!(io.poll_flush(cx));
+        assert_ready_ok!(poll_flush_bytes(io, cx));
     });
 }
 
@@ -453,9 +473,31 @@ fn write_single_frame_one_packet() {
     pin_mut!(io);
 
     task::spawn(()).enter(|cx, _| {
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("abcdefghi")));
-        assert_ready_ok!(io.as_mut().poll_flush(cx));
+        assert_ready_ok!(poll_flush_bytes(io.as_mut(), cx));
+        assert!(io.get_ref().calls.is_empty());
+    });
+}
+
+#[test]
+fn write_single_frame_from_slice() {
+    let io = FramedWrite::new(
+        mock! {
+            data(b"\x00\x00\x00\x09"),
+            data(b"abcdefghi"),
+            flush(),
+        },
+        LengthDelimitedCodec::new(),
+    );
+    pin_mut!(io);
+
+    task::spawn(()).enter(|cx, _| {
+        let data: &[u8] = b"abcdefghi";
+
+        assert_ready_ok!(Sink::<&[u8]>::poll_ready(io.as_mut(), cx));
+        assert_ok!(io.as_mut().start_send(data));
+        assert_ready_ok!(Sink::<&[u8]>::poll_flush(io.as_mut(), cx));
         assert!(io.get_ref().calls.is_empty());
     });
 }
@@ -477,16 +519,16 @@ fn write_single_multi_frame_one_packet() {
     pin_mut!(io);
 
     task::spawn(()).enter(|cx, _| {
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("abcdefghi")));
 
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("123")));
 
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("hello world")));
 
-        assert_ready_ok!(io.as_mut().poll_flush(cx));
+        assert_ready_ok!(poll_flush_bytes(io.as_mut(), cx));
         assert!(io.get_ref().calls.is_empty());
     });
 }
@@ -510,20 +552,20 @@ fn write_single_multi_frame_multi_packet() {
     pin_mut!(io);
 
     task::spawn(()).enter(|cx, _| {
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("abcdefghi")));
 
-        assert_ready_ok!(io.as_mut().poll_flush(cx));
+        assert_ready_ok!(poll_flush_bytes(io.as_mut(), cx));
 
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("123")));
 
-        assert_ready_ok!(io.as_mut().poll_flush(cx));
+        assert_ready_ok!(poll_flush_bytes(io.as_mut(), cx));
 
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("hello world")));
 
-        assert_ready_ok!(io.as_mut().poll_flush(cx));
+        assert_ready_ok!(poll_flush_bytes(io.as_mut(), cx));
         assert!(io.get_ref().calls.is_empty());
     });
 }
@@ -544,12 +586,12 @@ fn write_single_frame_would_block() {
     pin_mut!(io);
 
     task::spawn(()).enter(|cx, _| {
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("abcdefghi")));
 
-        assert_pending!(io.as_mut().poll_flush(cx));
-        assert_pending!(io.as_mut().poll_flush(cx));
-        assert_ready_ok!(io.as_mut().poll_flush(cx));
+        assert_pending!(poll_flush_bytes(io.as_mut(), cx));
+        assert_pending!(poll_flush_bytes(io.as_mut(), cx));
+        assert_ready_ok!(poll_flush_bytes(io.as_mut(), cx));
 
         assert!(io.get_ref().calls.is_empty());
     });
@@ -567,10 +609,10 @@ fn write_single_frame_little_endian() {
     pin_mut!(io);
 
     task::spawn(()).enter(|cx, _| {
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("abcdefghi")));
 
-        assert_ready_ok!(io.as_mut().poll_flush(cx));
+        assert_ready_ok!(poll_flush_bytes(io.as_mut(), cx));
         assert!(io.get_ref().calls.is_empty());
     });
 }
@@ -587,10 +629,10 @@ fn write_single_frame_with_short_length_field() {
     pin_mut!(io);
 
     task::spawn(()).enter(|cx, _| {
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("abcdefghi")));
 
-        assert_ready_ok!(io.as_mut().poll_flush(cx));
+        assert_ready_ok!(poll_flush_bytes(io.as_mut(), cx));
 
         assert!(io.get_ref().calls.is_empty());
     });
@@ -604,7 +646,7 @@ fn write_max_frame_len() {
     pin_mut!(io);
 
     task::spawn(()).enter(|cx, _| {
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_err!(io.as_mut().start_send(Bytes::from("abcdef")));
 
         assert!(io.get_ref().calls.is_empty());
@@ -621,10 +663,10 @@ fn write_update_max_frame_len_at_rest() {
     pin_mut!(io);
 
     task::spawn(()).enter(|cx, _| {
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("abcdef")));
 
-        assert_ready_ok!(io.as_mut().poll_flush(cx));
+        assert_ready_ok!(poll_flush_bytes(io.as_mut(), cx));
 
         io.encoder_mut().set_max_frame_length(5);
 
@@ -646,14 +688,14 @@ fn write_update_max_frame_len_in_flight() {
     pin_mut!(io);
 
     task::spawn(()).enter(|cx, _| {
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("abcdef")));
 
-        assert_pending!(io.as_mut().poll_flush(cx));
+        assert_pending!(poll_flush_bytes(io.as_mut(), cx));
 
         io.encoder_mut().set_max_frame_length(5);
 
-        assert_ready_ok!(io.as_mut().poll_flush(cx));
+        assert_ready_ok!(poll_flush_bytes(io.as_mut(), cx));
 
         assert_err!(io.as_mut().start_send(Bytes::from("abcdef")));
         assert!(io.get_ref().calls.is_empty());
@@ -666,10 +708,10 @@ fn write_zero() {
     pin_mut!(io);
 
     task::spawn(()).enter(|cx, _| {
-        assert_ready_ok!(io.as_mut().poll_ready(cx));
+        assert_ready_ok!(poll_ready_bytes(io.as_mut(), cx));
         assert_ok!(io.as_mut().start_send(Bytes::from("abcdef")));
 
-        assert_ready_err!(io.as_mut().poll_flush(cx));
+        assert_ready_err!(poll_flush_bytes(io.as_mut(), cx));
 
         assert!(io.get_ref().calls.is_empty());
     });