anchor.diff:        } else {
           var periodic = timer as _PausablePeriodicTimer;
   
  -        periodic.cancel();
  -
           var unpause = continueResumeWithPeriodicAt(scheduled, periodic,
               nextPeriodic: nextPeriodic);
           unpause.startFrom(offset);
  
positive.code:   _PausableNonPeriodicTimer continueResumeWithPeriodicAt(
        _Scheduled scheduled, _PausablePeriodicTimer periodic,
        {Duration nextPeriodic}) {
      var timer = _PausableNonPeriodicTimer.forPeriodic(
          this,
          scheduled.sequence,
  
negative.code:     _zone.resume();
    }
  
    Duration get parentOffset => _zone.parentOffset;
  
    Duration get offset => _zone.offset;
  }
  