feat(body): replace Chunk type with Bytes

Closes #1931

BREAKING CHANGE: All usage of `hyper::Chunk` should be replaced with
  `bytes::Bytes` (or `hyper::body::Bytes`).

src/body/body.rs

@@ -11,13 +11,12 @@ use futures_util::TryStreamExt;
 use http::HeaderMap;
 use http_body::{Body as HttpBody, SizeHint};
 
-use super::Chunk;
 use crate::common::{task, Future, Never, Pin, Poll};
 use crate::upgrade::OnUpgrade;
 
-type BodySender = mpsc::Sender<Result<Chunk, crate::Error>>;
+type BodySender = mpsc::Sender<Result<Bytes, crate::Error>>;
 
-/// A stream of `Chunk`s, used when receiving bodies.
+/// A stream of `Bytes`s, used when receiving bodies.
 ///
 /// A good default `Payload` to use in many applications.
 #[must_use = "streams do nothing unless polled"]
@@ -29,11 +28,11 @@ pub struct Body {
 }
 
 enum Kind {
-    Once(Option<Chunk>),
+    Once(Option<Bytes>),
     Chan {
         content_length: Option<u64>,
         abort_rx: oneshot::Receiver<()>,
-        rx: mpsc::Receiver<Result<Chunk, crate::Error>>,
+        rx: mpsc::Receiver<Result<Bytes, crate::Error>>,
     },
     H2 {
         content_length: Option<u64>,
@@ -45,7 +44,7 @@ enum Kind {
     // See https://github.com/rust-lang/rust/issues/57017
     #[cfg(feature = "stream")]
     Wrapped(
-        Pin<Box<dyn Stream<Item = Result<Chunk, Box<dyn StdError + Send + Sync>>> + Send + Sync>>,
+        Pin<Box<dyn Stream<Item = Result<Bytes, Box<dyn StdError + Send + Sync>>> + Send + Sync>>,
     ),
 }
 
@@ -152,7 +151,7 @@ impl Body {
     pub fn wrap_stream<S, O, E>(stream: S) -> Body
     where
         S: Stream<Item = Result<O, E>> + Send + Sync + 'static,
-        O: Into<Chunk> + 'static,
+        O: Into<Bytes> + 'static,
         E: Into<Box<dyn StdError + Send + Sync>> + 'static,
     {
         let mapped = stream.map_ok(Into::into).map_err(Into::into);
@@ -208,7 +207,7 @@ impl Body {
         })
     }
 
-    fn poll_eof(&mut self, cx: &mut task::Context<'_>) -> Poll<Option<crate::Result<Chunk>>> {
+    fn poll_eof(&mut self, cx: &mut task::Context<'_>) -> Poll<Option<crate::Result<Bytes>>> {
         match self.take_delayed_eof() {
             Some(DelayEof::NotEof(mut delay)) => match self.poll_inner(cx) {
                 ok @ Poll::Ready(Some(Ok(..))) | ok @ Poll::Pending => {
@@ -237,7 +236,7 @@ impl Body {
         }
     }
 
-    fn poll_inner(&mut self, cx: &mut task::Context<'_>) -> Poll<Option<crate::Result<Chunk>>> {
+    fn poll_inner(&mut self, cx: &mut task::Context<'_>) -> Poll<Option<crate::Result<Bytes>>> {
         match self.kind {
             Kind::Once(ref mut val) => Poll::Ready(val.take().map(Ok)),
             Kind::Chan {
@@ -265,7 +264,7 @@ impl Body {
             } => match ready!(h2.poll_data(cx)) {
                 Some(Ok(bytes)) => {
                     let _ = h2.flow_control().release_capacity(bytes.len());
-                    Poll::Ready(Some(Ok(Chunk::from(bytes))))
+                    Poll::Ready(Some(Ok(bytes)))
                 }
                 Some(Err(e)) => Poll::Ready(Some(Err(crate::Error::new_body(e)))),
                 None => Poll::Ready(None),
@@ -279,7 +278,7 @@ impl Body {
         }
     }
 
-    pub(super) fn take_full_data(&mut self) -> Option<Chunk> {
+    pub(super) fn take_full_data(&mut self) -> Option<Bytes> {
         if let Kind::Once(ref mut chunk) = self.kind {
             chunk.take()
         } else {
@@ -297,7 +296,7 @@ impl Default for Body {
 }
 
 impl HttpBody for Body {
-    type Data = Chunk;
+    type Data = Bytes;
     type Error = crate::Error;
 
     fn poll_data(
@@ -362,7 +361,7 @@ impl fmt::Debug for Body {
         #[derive(Debug)]
         struct Empty;
         #[derive(Debug)]
-        struct Full<'a>(&'a Chunk);
+        struct Full<'a>(&'a Bytes);
 
         let mut builder = f.debug_tuple("Body");
         match self.kind {
@@ -381,7 +380,7 @@ impl fmt::Debug for Body {
 /// `Cargo.toml`.
 #[cfg(feature = "stream")]
 impl Stream for Body {
-    type Item = crate::Result<Chunk>;
+    type Item = crate::Result<Bytes>;
 
     fn poll_next(self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Option<Self::Item>> {
         HttpBody::poll_data(self, cx)
@@ -393,22 +392,22 @@ impl Stream for Body {
 /// This function requires enabling the `stream` feature in your
 /// `Cargo.toml`.
 #[cfg(feature = "stream")]
-impl From<Box<dyn Stream<Item = Result<Chunk, Box<dyn StdError + Send + Sync>>> + Send + Sync>>
+impl From<Box<dyn Stream<Item = Result<Bytes, Box<dyn StdError + Send + Sync>>> + Send + Sync>>
     for Body
 {
     #[inline]
     fn from(
         stream: Box<
-            dyn Stream<Item = Result<Chunk, Box<dyn StdError + Send + Sync>>> + Send + Sync,
+            dyn Stream<Item = Result<Bytes, Box<dyn StdError + Send + Sync>>> + Send + Sync,
         >,
     ) -> Body {
         Body::new(Kind::Wrapped(stream.into()))
     }
 }
 
-impl From<Chunk> for Body {
+impl From<Bytes> for Body {
     #[inline]
-    fn from(chunk: Chunk) -> Body {
+    fn from(chunk: Bytes) -> Body {
         if chunk.is_empty() {
             Body::empty()
         } else {
@@ -417,24 +416,17 @@ impl From<Chunk> for Body {
     }
 }
 
-impl From<Bytes> for Body {
-    #[inline]
-    fn from(bytes: Bytes) -> Body {
-        Body::from(Chunk::from(bytes))
-    }
-}
-
 impl From<Vec<u8>> for Body {
     #[inline]
     fn from(vec: Vec<u8>) -> Body {
-        Body::from(Chunk::from(vec))
+        Body::from(Bytes::from(vec))
     }
 }
 
 impl From<&'static [u8]> for Body {
     #[inline]
     fn from(slice: &'static [u8]) -> Body {
-        Body::from(Chunk::from(slice))
+        Body::from(Bytes::from(slice))
     }
 }
 
@@ -451,14 +443,14 @@ impl From<Cow<'static, [u8]>> for Body {
 impl From<String> for Body {
     #[inline]
     fn from(s: String) -> Body {
-        Body::from(Chunk::from(s.into_bytes()))
+        Body::from(Bytes::from(s.into_bytes()))
     }
 }
 
 impl From<&'static str> for Body {
     #[inline]
     fn from(slice: &'static str) -> Body {
-        Body::from(Chunk::from(slice.as_bytes()))
+        Body::from(Bytes::from(slice.as_bytes()))
     }
 }
 
@@ -486,7 +478,7 @@ impl Sender {
     }
 
     /// Send data on this channel when it is ready.
-    pub async fn send_data(&mut self, chunk: Chunk) -> crate::Result<()> {
+    pub async fn send_data(&mut self, chunk: Bytes) -> crate::Result<()> {
         futures_util::future::poll_fn(|cx| self.poll_ready(cx)).await?;
         self.tx
             .try_send(Ok(chunk))
@@ -497,15 +489,15 @@ impl Sender {
     ///
     /// # Errors
     ///
-    /// Returns `Err(Chunk)` if the channel could not (currently) accept
-    /// another `Chunk`.
+    /// Returns `Err(Bytes)` if the channel could not (currently) accept
+    /// another `Bytes`.
     ///
     /// # Note
     ///
     /// This is mostly useful for when trying to send from some other thread
     /// that doesn't have an async context. If in an async context, prefer
     /// [`send_data`][] instead.
-    pub fn try_send_data(&mut self, chunk: Chunk) -> Result<(), Chunk> {
+    pub fn try_send_data(&mut self, chunk: Bytes) -> Result<(), Bytes> {
         self.tx
             .try_send(Ok(chunk))
             .map_err(|err| err.into_inner().expect("just sent Ok"))