Add Server.isClosed and Client.isClosed.

lib/src/two_way_stream.dart

Index: lib/src/two_way_stream.dart
diff --git a/lib/src/two_way_stream.dart b/lib/src/two_way_stream.dart
index 5914173876f6d21799bfdcc1c34cd45471c71852..5644c126621a060bb7c6b79f265a4ab9e4468ceb 100644
--- a/lib/src/two_way_stream.dart
+++ b/lib/src/two_way_stream.dart
@@ -38,6 +38,10 @@ class TwoWayStream {
   Future get done => _doneCompleter.future;
   final _doneCompleter = new Completer();
 
+  /// Whether the stream has been closed.
+  bool get isClosed => _isClosed;

[Bob Nystrom, 2015/09/03 18:13:03]

Can this just be => _doneCompleter.isCompleted?

[nweiz, 2015/09/08 21:17:32]

Done.

+  bool _isClosed = false;
+
   /// Creates a two-way stream.
   ///
   /// [input] and [output] should emit and take (respectively) JSON-encoded
@@ -123,6 +127,7 @@ class TwoWayStream {
       throw new StateError("Can't call $_name.close before $_name.listen.");
     }
 
+    _isClosed = true;
     if (!_doneCompleter.isCompleted) _doneCompleter.complete();
 
     var inputFuture = _inputSubscription.cancel();