该帧的独立于 timeScale 的时间（只读）。此为自游戏启动以来的时间（以秒为单位）。
Double precision version of unscaledTimeAsDouble. This offers more precision than a float or single value, particularly over extended periods of real-world time. In almost all cases, choose the unscaledTimeAsDouble equivalent over unscaledTime.
When called from inside MonoBehaviour's FixedUpdate, returns the unscaled fixed time.
Returns the same value if called multiple times in a single frame. Unlike timeAsDouble this value is not affected by timeScale.