Golang httptrace 的示例—

package main

import (
    "fmt"
    "log"
    "net/http"
    "net/http/httptrace"
)

func main() {
    req, _ := http.NewRequest(http.MethodGet, "http://example.com", nil)
    clientTrace := &httptrace.ClientTrace{
        GetConn:      func(hostPort string) { fmt.Println("starting to create conn ", hostPort) },
        DNSStart:     func(info httptrace.DNSStartInfo) { fmt.Println("starting to look up dns", info) },
        DNSDone:      func(info httptrace.DNSDoneInfo) { fmt.Println("done looking up dns", info) },
        ConnectStart: func(network, addr string) { fmt.Println("starting tcp connection", network, addr) },
        ConnectDone:  func(network, addr string, err error) { fmt.Println("tcp connection created", network, addr, err) },
        GotConn:      func(info httptrace.GotConnInfo) { fmt.Println("connection established", info) },
    }
    clientTraceCtx := httptrace.WithClientTrace(req.Context(), clientTrace)
    req = req.WithContext(clientTraceCtx)
    _, err := http.DefaultClient.Do(req)
    if err != nil {
        log.Fatal(err)
    }
}

运行结果 :