golang http client不使用连接池

    client := &http.Client{
        Transport: &http.Transport{
            DialContext: (&net.Dialer{
                Timeout:   5 * time.Second,
                KeepAlive: 5 * time.Second,
            }).DialContext,
            TLSHandshakeTimeout:   5 * time.Second,
            ResponseHeaderTimeout: 5 * time.Second,
            ExpectContinueTimeout: 1 * time.Second,
            DisableKeepAlives: true,
        },
    }