帧可以在粒子更新上耗用的最长时间。如果帧耗用的时间超过该值，则将更新拆分为多个较小的更新。
使用该函数可在粒子模拟的准确性与性能目标之间取得平衡。
Using a small value gives higher quality particle simulations, but takes more processing time. Particle updates run multiple times at smaller time increments,
if the frame time exceeds the threshold provided.
Conversely, a higher value ensures that particle simulations are not broken down into multiple steps per frame, giving the best performance, but loses simulation
accuracy when using some of the more advanced particle simulation features.