golang框架如何使用熔断模式保护后端服务？

package main

import (
    "fmt"
    "net/http"
    "time"

    "github.com/go-kit/kit/circuitbreaker"
    "github.com/go-kit/kit/log"
    "github.com/go-kit/kit/tracing/opentracing"
    httptransport "github.com/go-kit/kit/transport/http"
    "github.com/opentracing/opentracing-go"
)

func main() {
    logger := log.NewLogfmtLogger(log.NewSyncWriter(os.Stdout))
    tracer := opentracing.GlobalTracer()

    // 设置熔断配置
    cb := circuitbreaker.New(cb.WithMaxFailures(3))
    wrappedHTTPClient := cb.Wrap(http.DefaultClient)

    // 创建 HTTP 传输
    transport := httptransport.NewClient(
        "GET",
        "http://localhost:8080",
        wrappedHTTPClient,
        opentracing.ClientTrace(tracer),
    )

    // 创建端点
    endpoint := httptransport.NewServer(
        transport,
        decodeRequest,
        encodeResponse,
        opentracing.ServerTrace(tracer),
    )

    // 创建 HTTP 处理程序
    handler := httptransport.NewServer(
        endpoint,
        decodeRequest,
        encodeResponse,
    )

    // 启动 HTTP 服务器
    srv := &http.Server{
        Addr:    ":8080",
        Handler: handler,
    }

    logger.Log("msg", "HTTP 服务器已启动")
    err := srv.ListenAndServe()
    if err != nil {
        logger.Log("err", err)
        return
    }
}

func decodeRequest(r *http.Request) (interface{}, error) {
    return nil, nil
}

func encodeResponse(w http.ResponseWriter, r interface{}) error {
    w.Header().Set("Content-Type", "application/json")
    fmt.Fprint(w, "Hello, World!")
    return nil
}