Fix all strong-mode errors and warnings.

lib/src/disconnector.dart

 // Copyright (c) 2016, 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.
 
 import 'dart:async';
 
 import '../stream_channel.dart';
 
 /// Allows the caller to force a channel to disconnect.
 ///
@@ skipping 20 matching lines @@
   void disconnect() {
     _isDisconnected = true;
     for (var sink in _sinks) {
       sink._disconnect();
     }
     _sinks.clear();
   }
 
   StreamChannel<T> bind(StreamChannel<T> channel) {
     return channel.changeSink((innerSink) {
-      var sink = new _DisconnectorSink(innerSink);
+      var sink = new _DisconnectorSink<T>(innerSink);
 
       if (_isDisconnected) {
         sink._disconnect();
       } else {
         _sinks.add(sink);
       }
 
       return sink;
     });
   }
@@ skipping 78 matching lines @@
   void _disconnect() {
     _isDisconnected = true;
     _inner.close();
 
     if (!_inAddStream) return;
     _addStreamCompleter.complete(_addStreamSubscription.cancel());
     _addStreamCompleter = null;
     _addStreamSubscription = null;
   }
 }