internal/clock/clock.go
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
}
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
}
// 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.