Add an OutputStream.closed getter.

runtime/bin/list_stream_impl.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Default implementation of [ListInputStream].
  */
 class _ListInputStream extends _BaseDataInputStream implements ListInputStream {
   _ListInputStream() : _bufferList = new _BufferList();
 
@@ skipping 53 matching lines @@
         copyBuffer: false);
   }
 
   void flush() {
     // Nothing to do on a list output stream.
   }
 
   void close() {
     if (_streamMarkedClosed) throw new StreamException.streamClosed();
     _streamMarkedClosed = true;
+    _checkScheduleCallbacks();
   }
 
   void destroy() {
     close();
   }
 
   void set onData(void callback()) {
     _clientDataHandler = callback;
     _checkScheduleCallbacks();
   }
@@ skipping 53 matching lines @@
         _scheduledNoPendingWriteCallback =
           new Timer(0, issueNoPendingWriteCallback);
       }
 
     } else if (_clientCloseHandler != null) {
       _scheduledCloseCallback = new Timer(0, issueCloseCallback);
       _closeCallbackCalled = true;
     }
   }
 
+  bool get closed() => _streamMarkedClosed;
+
   _BufferList _bufferList;
   bool _streamMarkedClosed = false;
   bool _closeCallbackCalled = false;
   Timer _scheduledDataCallback;
   Timer _scheduledNoPendingWriteCallback;
   Timer _scheduledCloseCallback;
   Function _clientDataHandler;
   Function _clientNoPendingWriteHandler;
   Function _clientCloseHandler;
 }