Change hasSubscribers to hasListener.

sdk/lib/io/io_sink.dart

 // Copyright (c) 2013, 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.
 
 part of dart.io;
 
 /**
  * Helper class to wrap a [StreamConsumer<List<int>>] and provide
  * utility functions for writing to the StreamConsumer directly. The
  * [IOSink] buffers the input given by [write], [writeAll], [writeln],
@@ skipping 218 matching lines @@
     if (_bindSubscription != null) {
       try {
         // The subscription can be canceled at this point.
         _bindSubscription.resume();
       } catch (e) {
       }
     }
   }
 
   void _onSubscriptionStateChange() {
-    if (_controller.hasSubscribers) {
+    if (_controller.hasListener) {
       _paused = false;
       _resume();
     } else {
       if (_bindSubscription != null) {
         _bindSubscription.cancel();
         _bindSubscription = null;
       }
     }
   }
 
@@ skipping 14 matching lines @@
         },
         onError: _controller.addError);
     if (_paused) _pause();
     if (unbind) {
       return _writeStreamCompleter.future;
     } else {
       return _pipeFuture;
     }
   }
 }