golang 统计代码执行时间

    start := time.Now()
    resp, err := client.Get(url)
    elapsed := time.Since(start)
    fmt.Println("该函数执行完成耗时：", elapsed)
    if err != nil {
        if elapsed >= 10*time.Second {
            log.Println("dail timeout", err)
            log.Println("网站不可用:", url)
            return 2
        }
        return 3
    }