code: func Update(tps int) int {
  	m.Lock()
  	defer m.Unlock()
  
  	n := now()
  	c := 0
  	if tps == UncappedTPS {
  		c = 1
  	} else if tps > 0 {
  		c = calcCountFromTPS(int64(tps), n)
  	}
  	updateFPSAndTPS(n, c)
  	return c
  }
docs: // Update updates the inner clock state and returns an integer value
  // indicating how many times the game should update based on given tps.
  // tps represents TPS (ticks per second).
  // If tps is UncappedTPS, Update always returns 1.
  // If tps <= 0 and not UncappedTPS, Update always returns 0.
  //
  // Update is expected to be called per frame.