https://zhuanlan.zhihu.com/p/393178103 https://github.com/yangwenmai/ratelimit/blob/master/example/main.go https://segmentfault.com/a/1190000041548601
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计数器 滑动日志算法 漏桶算法 令牌桶算法
https://github.com/yangwenmai/ratelimit https://github.com/golang/time/blob/master/rate/rate.go