使用标头在Golang中发送POST请求

form := url.Values{}
form.Add("region", "San Francisco")
if len(params) > 0 { 
    for i := 0; i < len(params); i += 2 { 
        form.Add(params[i], params[i+1])
    }
    testLog.Infof("form %v", form)

resp, err = http.PostForm(address+r.Path, form)

req, err := http.NewRequest("POST", address+r.Path, strings.NewReader(form.Encode()))

req.Header.Add("region", "San Francisco") 
resp, err = http.DefaultClient.Do(req)

&{POST http://localhost:8081/login HTTP/1.1 1 1 map[Region:[San Francisco]] {0xc420553600} 78 [] false localhost:8081 map[] map[] <nil> map[]   <nil> <nil> <nil> <nil>}