(This set of tutorials focuses on Sentinel's core workflow and sliding time window current limiting algorithm. First, explain the principle in detail. On the premise of a thorough understanding of the principle, it will take you to have an in-depth understanding of Sentinel's source code. Through the analysis of Sentinel's core source code, you will have an in-depth understanding of Sentinel's underlying working principle and workflow, and clearly understand how current limiting, fusing and degradation are completed.)