Go语言HTTP客户端设置IP_TOS

        dialer := &net.Dialer{
		Control: func(network, address string, c syscall.RawConn) error {
			return c.Control(func(fd uintptr) {
				err := syscall.SetsockoptInt(int(fd), syscall.IPPROTO_IP, syscall.IP_TOS, 15)
				if err != nil {
					log.Printf("control: %s", err)
					return
				}
			})
		},
	}
	tr := &http.Transport{
		Proxy:                 http.ProxyFromEnvironment,
		DialContext:           dialer.DialContext,
		MaxIdleConns:          100,
		IdleConnTimeout:       90 * time.Second,
		TLSHandshakeTimeout:   10 * time.Second,
		ExpectContinueTimeout: 1 * time.Second,
	}

	c := &http.Client{
		Transport: tr,
	}