Implement Stream for Receiver

That's... what it is!

src/channel.rs

@@ -2,6 +2,7 @@ use std::io;
 use std::sync::mpsc::TryRecvError;
 
 use futures::{Future, Poll};
+use futures::stream::Stream;
 use futures_io::IoFuture;
 use mio::channel;
 
@@ -20,10 +21,11 @@ pub struct Sender<T> {
 /// The receiving half of a channel used for processing messages sent by a
 /// `Sender`.
 ///
-/// A `Receiver` cannot be cloned and is not `Sync`, so only one thread can
-/// receive messages at a time.
+/// A `Receiver` cannot be cloned, so only one thread can receive messages at a
+/// time.
 ///
-/// This type is created by the `LoopHandle::channel` method.
+/// This type is created by the `LoopHandle::channel` method and implements the
+/// `Stream` trait to represent received messages.
 pub struct Receiver<T> {
     rx: ReadinessStream<channel::Receiver<T>>,
 }
@@ -80,28 +82,18 @@ impl<T> Clone for Sender<T> {
     }
 }
 
-impl<T> Receiver<T> {
-    /// Attempts to receive a message sent on this channel.
-    ///
-    /// This method will attempt to dequeue any messages sent on this channel
-    /// from any corresponding sender. If no message is available, but senders
-    /// are still detected, then `Poll::NotReady` is returned and the current
-    /// future task is scheduled to receive a notification when a message is
-    /// available.
-    ///
-    /// If an I/O error happens or if all senders have gone away (the channel is
-    /// disconnected) then `Poll::Err` will be returned.
-    pub fn recv(&self) -> Poll<T, io::Error> {
+impl<T> Stream for Receiver<T> {
+    type Item = T;
+    type Error = io::Error;
+
+    fn poll(&mut self) -> Poll<Option<T>, io::Error> {
         match self.rx.get_ref().try_recv() {
-            Ok(t) => Poll::Ok(t),
+            Ok(t) => Poll::Ok(Some(t)),
             Err(TryRecvError::Empty) => {
                 self.rx.need_read();
                 Poll::NotReady
             }
-            Err(TryRecvError::Disconnected) => {
-                Poll::Err(io::Error::new(io::ErrorKind::Other,
-                                         "channel has been disconnected"))
-            }
+            Err(TryRecvError::Disconnected) => Poll::Ok(None),
         }
     }
 }