如何在Golang中设置GODEBUG环境变量，以便可以在net/http中使用godebug

package main

import (
	"fmt"
	"net/http"
	"net/http/httputil"
	"os"
)

func main() {
	// 创建一个自定义的Transport，用于打印HTTP请求和响应的调试信息
	transport := &http.Transport{
		Proxy: http.ProxyFromEnvironment,
		DialContext: (&net.Dialer{
			Timeout:   30 * time.Second,
			KeepAlive: 30 * time.Second,
			DualStack: true,
		}).DialContext,
		MaxIdleConns:          100,
		IdleConnTimeout:       90 * time.Second,
		TLSHandshakeTimeout:   10 * time.Second,
		ExpectContinueTimeout: 1 * time.Second,
	}

	// 创建一个自定义的Client，使用自定义的Transport
	client := &http.Client{
		Transport: transport,
	}

	// 创建一个HTTP请求
	req, err := http.NewRequest("GET", "https://www.example.com", nil)
	if err != nil {
		fmt.Println("Failed to create request:", err)
		os.Exit(1)
	}

	// 打印HTTP请求的调试信息
	requestDump, err := httputil.DumpRequestOut(req, true)
	if err != nil {
		fmt.Println("Failed to dump request:", err)
		os.Exit(1)
	}
	fmt.Println("Request:")
	fmt.Println(string(requestDump))

	// 发送HTTP请求并获取响应
	resp, err := client.Do(req)
	if err != nil {
		fmt.Println("Failed to send request:", err)
		os.Exit(1)
	}
	defer resp.Body.Close()

	// 打印HTTP响应的调试信息
	responseDump, err := httputil.DumpResponse(resp, true)
	if err != nil {
		fmt.Println("Failed to dump response:", err)
		os.Exit(1)
	}
	fmt.Println("Response:")
	fmt.Println(string(responseDump))
}