Fix checked mode error on socket IOSink

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>, T>] and provide
  * utility functions for writing to the StreamConsumer directly. The
  * [IOSink] buffers the input given by [write], [writeAll], [writeln],
@@ skipping 51 matching lines @@
   Future<T> _pipeFuture;
   StreamSubscription<List<int>> _bindSubscription;
   bool _paused = true;
   bool _encodingMutable = true;
 
   _IOSinkImpl(StreamConsumer<List<int>, T> this._target, this._encoding);
 
   Encoding _encoding;
 
   Encoding get encoding => _encoding;
+
   void set encoding(Encoding value) {
     if (!_encodingMutable) {
       throw new StateError("IOSink encoding is not mutable");
     }
     _encoding = value;
   }
 
   void write(Object obj) {
     // This comment is copied from runtime/lib/string_buffer_patch.dart.
     // TODO(srdjan): The following four lines could be replaced by
@@ skipping 142 matching lines @@
         },
         onError: _controller.addError);
     if (_paused) _pause();
     if (unbind) {
       return _writeStreamCompleter.future;
     } else {
       return _pipeFuture.then((_) => this);
     }
   }
 }