Specify a closed stream with the CANCEL code as valid

src/proto/streams/recv.rs

@@ -318,7 +318,9 @@ impl Recv {
             Some(Event::Headers(Client(response))) => Poll::Ready(Ok(response)),
             Some(_) => panic!("poll_response called after response returned"),
             None => {
-                stream.state.ensure_recv_open()?;
+                if !stream.state.ensure_recv_open()? {
+                    return Poll::Ready(Ok(Response::new(())));
+                }
 
                 stream.recv_task = Some(cx.waker().clone());
                 Poll::Pending

src/proto/streams/state.rs

@@ -433,6 +433,7 @@ impl State {
     pub fn ensure_recv_open(&self) -> Result<bool, proto::Error> {
         // TODO: Is this correct?
         match self.inner {
+            Closed(Cause::Error(Error::Reset(_, Reason::CANCEL, _))) => Ok(false),
             Closed(Cause::Error(ref e)) => Err(e.clone()),
             Closed(Cause::ScheduledLibraryReset(reason)) => {
                 Err(proto::Error::library_go_away(reason))

src/proto/streams/streams.rs

@@ -726,7 +726,10 @@ impl Inner {
                 }
 
                 // The stream must be receive open
-                stream.state.ensure_recv_open()?;
+                if !stream.state.ensure_recv_open()? {
+                    return Ok(());
+                }
+
                 stream.key()
             }
             None => {