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: 
    @override
    void cancel() {
      onFinish();
  
      if (!live)
        return;
      live = false;
  