Change hasSubscribers to hasListener.

sdk/lib/io/file_impl.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;
 
 // Read the file in blocks of size 64k.
 const int _BLOCK_SIZE = 64 * 1024;
 
 
@@ skipping 112 matching lines @@
     _paused = false;
     if (_currentBlock != null) {
       _controller.add(_currentBlock);
       _currentBlock = null;
     }
     // Resume reading unless we are already done.
     if (_openedFile != null) _readBlock();
   }
 
   void _onSubscriptionStateChange() {
-    if (_controller.hasSubscribers) {
+    if (_controller.hasListener) {
       _start();
     } else {
       _unsubscribed = true;
       _closeFile();
     }
   }
 
   void _onPauseStateChange() {
     if (_controller.isPaused) {
       _paused = true;
@@ skipping 910 matching lines @@
           new FileIOException("File closed '$_path'"));
     });
     return completer.future;
   }
 
   final String _path;
   int _id;
 
   SendPort _fileService;
 }