anchor.diff:  
     _config.onStart();
   
  -  new Future(_nextBatch);
  +  _defer(() {
  +    _nextBatch();
  +  });
   }
   
   /**
  
positive.code: // TODO(sigmund): deprecate this API when issue 2706 is fixed.
  Function expectAsyncUntil2(Function callback, Function isDone, {String id}) {
    return new _SpreadArgsHelper(callback, 0, -1, isDone, id).invoke2;
  }
  
  /**
  
negative.code:   final int minExpectedCalls;
    final int maxExpectedCalls;
    final Function isDone;
    final int testNum;
    final String id;
    int actualCalls = 0;
    TestCase testCase;
    bool complete;
    static const sentinel = const _Sentinel();
  
  