inpututil/inpututil.go
func KeyPressDuration(key ebiten.Key) int {
	theInputState.m.RLock()
	s := theInputState.keyDurations[key]
	theInputState.m.RUnlock()
	return s
}
func KeyPressDuration(key ebiten.Key) int {
	theInputState.m.RLock()
	s := theInputState.keyDurations[key]
	theInputState.m.RUnlock()
	return s
}
// KeyPressDuration returns how long the key is pressed in frames.
//
// KeyPressDuration is concurrent safe.