Set Stream types as must_use

src/channel.rs

@@ -37,6 +37,7 @@ pub struct Sender<T> {
 /// `Stream` trait to represent received messages.
 ///
 /// [`channel`]: fn.channel.html
+#[must_use = "streams do nothing unless polled"]
 pub struct Receiver<T> {
     rx: PollEvented<channel::Receiver<T>>,
 }

src/io/frame.rs

@@ -310,6 +310,7 @@ pub trait Codec {
 /// the `Codec` trait to encode and decode frames.
 ///
 /// You can acquire a `Framed` instance by using the `Io::framed` adapter.
+#[must_use = "streams do nothing unless polled"]
 pub struct Framed<T, C> {
     upstream: T,
     codec: C,

src/net/tcp.rs

@@ -25,6 +25,7 @@ pub struct TcpListener {
 
 /// Stream returned by the `TcpListener::incoming` function representing the
 /// stream of sockets received from a listener.
+#[must_use = "streams do nothing unless polled"]
 pub struct Incoming {
     inner: TcpListener,
 }

src/reactor/interval.rs

@@ -21,6 +21,7 @@ use reactor::timeout_token::TimeoutToken;
 /// Note that timeouts are not intended for high resolution timers, but rather
 /// they will likely fire some granularity after the exact instant that they're
 /// otherwise indicated to fire at.
+#[must_use = "streams do nothing unless polled"]
 pub struct Interval {
     token: TimeoutToken,
     next: Instant,