split Client into (Client, Connection) (#107)

The Connection type is a `Future` that drives all of the IO of the
client connection.

The Client type is separate, and is used to send requests into the
connection.

tests/support/mock.rs

@@ -480,7 +480,7 @@ where
             Async::Ready((frame, handle)) => (frame, handle),
             Async::NotReady => return Ok(Async::NotReady),
         };
-        assert_eq!(frame.unwrap(), self.frame);
+        assert_eq!(frame.unwrap(), self.frame, "recv_frame");
         Ok(Async::Ready(handle))
     }
 }

tests/support/mod.rs

@@ -1,5 +1,11 @@
 //! Utilities to support tests.
 
+#[cfg(not(feature = "unstable"))]
+compile_error!(
+    "Tests depend on the 'unstable' feature on h2. \
+    Retry with `cargo test --features unstable`"
+);
+
 pub extern crate bytes;
 pub extern crate env_logger;
 pub extern crate futures;

tests/support/prelude.rs

@@ -60,7 +60,7 @@ pub trait ClientExt {
     fn run<F: Future>(&mut self, f: F) -> Result<F::Item, F::Error>;
 }
 
-impl<T, B> ClientExt for Client<T, B>
+impl<T, B> ClientExt for client::Connection<T, B>
 where
     T: AsyncRead + AsyncWrite + 'static,
     B: IntoBuf + 'static,