Add a DelegatingStreamChannel class.

lib/src/delegating_stream_channel.dart

Index: lib/src/delegating_stream_channel.dart
diff --git a/lib/src/delegating_stream_channel.dart b/lib/src/delegating_stream_channel.dart
new file mode 100644
index 0000000000000000000000000000000000000000..9d6ad90fdca3d113c9317dd93dbfb757763a810e
--- /dev/null
+++ b/lib/src/delegating_stream_channel.dart
@@ -0,0 +1,17 @@
+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// A simple delegating wrapper around [StreamChannel].
+///
+/// Subclasses can override individual methods, or use this to expose only
+/// [StreamChannel] methods.
+class StreamChannelView<T> extends StreamChannelMixin<T> {
+  /// The inner channel to which methods are forwarded.
+  final StreamChannel<T> _inner;
+
+  Stream<T> get stream => _inner.stream;
+  StreamSink<T> get sink => _inner.sink;
+
+  StreamChannelView(this._inner);
+}