response, err := gout.New().
                WithContext(ctx).
		SetTimeout(100 * time.Second).
		
		SetMethod("POST").
		SetURL(url).
		SetJSON(request).
		Response()
if err != nil {
    panic(err.Error())
}
defer response.Body.Close()

// 读取Response.Body
for {
  _, err :=  response.Body.Read(....)
}

func (s *Setting) SetTimeout(d time.Duration) {
	s.Index++
	s.TimeoutIndex = s.Index
	s.Timeout = d
}

// retry模块需要context.Context，所以这里也返回context.Context
func (r *Req) GetContext() context.Context {
	if r.Timeout > 0 && r.TimeoutIndex > r.ctxIndex {
		r.c, r.cancel = context.WithTimeout(context.Background(), r.Timeout)  // 当`WithContext(ctx)`在`SetTimeout`上面时，会执行此行
	}
	return r.c
}

// Response 获取原始http.Response数据结构
func (r *Req) Response() (rsp *http.Response, err error) {
	_, rsp, err = r.getReqAndRsp()
	defer r.Reset()   // 此处会调用r.cancel 
	return
}