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)
}

} ···