初学golang，帮忙看看问题出在哪里，谢谢

··· func main() { TR := &http.Transport{ MaxIdleConns: 10, IdleConnTimeout: 30 * time.Second, DisableCompression: true, } CLIENT := &http.Client{Transport: TR} server01 := &http.Server{ Addr: ":8080", Handler: router01(), ReadTimeout: 5 * time.Second, WriteTimeout: 10 * time.Second, } server02 := &http.Server{ Addr: ":8081", Handler: router02(), ReadTimeout: 5 * time.Second, WriteTimeout: 10 * time.Second, } g.Go(func() error { // 下面这句是能看到输出的 log.Println("start server01") err := server01.ListenAndServe() //下面这句就看不到输出了。 // 这段代码是想在下面在server01启动以后，等待5秒钟（等server02启动）后，在server01里向server02发起一个请求 log.Println("server01 started") if err != nil && err != http.ErrServerClosed { log.Fatal(err) } //等待5秒 time.Sleep(5 * time.Second) log.Println("Begin reg") //向server01发起请求 resp, err := CLIENT.PostForm("http://localhost:8081/reg", url.Values{"sid": {"1234567"}, "sip": {"127.0.0.1"}}) if err != nil { log.Println("reg error") } defer resp.Body.Close() //body, err := ioutil.ReadAll(resp.Body) return err }) g.Go(func() error { err := server02.ListenAndServe() if err != nil && err != http.ErrServerClosed { log.Fatal(err) } return err }) if err := g.Wait(); err != nil { log.Fatal(err) } } ···