抄的kratos , 在滑块中添加缓存, 并修复了kratos中apply的一个小BUG, 见 https://github.com/go-kratos/aegis/issues/17

kratos: https://github.com/go-kratos/kratos/blob/main/middleware/circuitbreaker/circuitbreaker.go sre: https://github.com/go-kratos/aegis/tree/main/circuitbreaker/sre window: https://github.com/go-kratos/aegis/tree/main/pkg/window