如何从http.Client添加默认标头字段

package main

import (
	"net/http"
)

type CustomTransport struct {
	Transport http.RoundTripper
}

func (t *CustomTransport) RoundTrip(req *http.Request) (*http.Response, error) {
	// 在这里添加默认的标头字段
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", "Bearer your_token")

	// 使用默认的Transport发送请求
	if t.Transport == nil {
		t.Transport = http.DefaultTransport
	}
	return t.Transport.RoundTrip(req)
}

func main() {
	client := &http.Client{
		Transport: &CustomTransport{},
	}

	req, err := http.NewRequest("GET", "http://example.com", nil)
	if err != nil {
		// 处理错误
	}

	resp, err := client.Do(req)
	if err != nil {
		// 处理错误
	}

	// 处理响应
	defer resp.Body.Close()
	// ...
}