anchor.diff:  
     @override
     void stop({ bool showElapsedTime: true }) {
  +    onFinish();
  +
       if (!live)
         return;
       live = false;
  
positive.code: }
  
  class _AnsiStatus extends Status {
    _AnsiStatus(this.message) {
      stopwatch = new Stopwatch()..start();
  
      stdout.write('${message.padRight(51)}     ');
  
negative.code:   void stop({ bool showElapsedTime: true }) { }
    void cancel() { }
  }
  
  typedef void _FinishCallback();
  
  class StdoutLogger extends Logger {
    Status _status;
  