package main        import (            "net/url"            "net/http"            "bytes"            "fmt"            "io/ioutil"        )        // 代理服务器(产品官网 www.16yun.cn)        const ProxyServer = "t.16yun.cn:31111"        type ProxyAuth struct {            Username string            Password string        }        func (p ProxyAuth) ProxyClient() http.Client {            var proxyURL *url.URL            if p.Username != ""&& p.Password!="" {                proxyURL, _ = url.Parse("http://" + p.Username + ":" + p.Password + "@" + ProxyServer)            }else{                proxyURL, _ = url.Parse("http://" + ProxyServer)            }            return http.Client{Transport: &http.Transport{Proxy:http.ProxyURL(proxyURL)}}        }        func main()  {            targetURI := "https://httpbin.org/ip"            // 初始化 proxy http client            client := ProxyAuth{"username",  "password"}.ProxyClient()            request, _ := http.NewRequest("GET", targetURI, bytes.NewBuffer([] byte(``)))            // 设置Proxy-Tunnel            // rand.Seed(time.Now().UnixNano())            // tunnel := rand.Intn(10000)            // request.Header.Set("Proxy-Tunnel", strconv.Itoa(tunnel) )            response, err := client.Do(request)            if err != nil {                panic("failed to connect: " + err.Error())            } else {                bodyByte, err := ioutil.ReadAll(response.Body)                if err != nil {                    fmt.Println("读取 Body 时出错", err)                    return                }                response.Body.Close()                body := string(bodyByte)                fmt.Println("Response Status:", response.Status)                fmt.Println("Response Header:", response.Header)                fmt.Println("Response Body:\n", body)            }        }