!7

module SteadyBeat {
  int interval = 50;
  
  transient long lastTick;
  transient long count, maxDelaySeen, averageSum;
  
  start {
    doEvery(interval, r tick);
  }
  
  void tick enter {
    long now = sysNow();
    long delay = now-lastTick;
    maxDelaySeen = max(maxDelaySeen, delay);
    ++count;
    averageSum += delay;
  }
  
  // API
  
  long average() {
    ret (averageSum+count/2)/count;
  }
}