anchor.diff:  // 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.
   
  +// ignore_for_file: prefer_initializing_formals
  +// ignore_for_file: unnecessary_new
  +// ignore_for_file: unnecessary_this
  +// ignore_for_file: unused_field
  +// ignore_for_file: unused_local_variable
  +// ignore_for_file: use_setters_to_change_properties
  +
  +import 'dart:async';
   import 'dart:io';
  -import 'dart:async';
   
   class MockIOSink implements Sink {
     @override
  
positive.code: 
  class B1 {
    Socket _socketB1;
    Future init(filename) async {
      _socketB1 = await Socket.connect(null /*address*/, 1234); // OK
    }
  
    void dispose(filename) {
      _socketB1.destroy();
    }
  }
  
negative.code: 
  class A {
    IOSink _sinkA; // LINT
    void init(String filename) {
      _sinkA = new File(filename).openWrite();
    }
  }
  
  class B {
    IOSink _sinkB;
    void init(String filename) {
      _sinkB = new File(filename).openWrite(); // OK
    }
  
  