if nt == "" {
				nt = network
			}
			addr := dnsServer
			if addr == "" {
				addr = address
			}
			return d.DialContext(ctx, nt, addr)
		},
	}
}

// doForward sends the requests and collect the responses.
func doForward(ctx context.Context, cfg *Config, e *executor, doReq func(context.Context, *Config, int) (string, error)) (*proto.ForwardEchoResponse, error) {
	// make the timeout apply to the entire set of requests

	e *executor
}

func newTCPProtocol(e *executor) protocol {
	return &tcpProtocol{e: e}
}

func (c *tcpProtocol) ForwardEcho(ctx context.Context, cfg *Config) (*proto.ForwardEchoResponse, error) {
	return doForward(ctx, cfg, c.e, c.makeRequest)
}

func (c *tcpProtocol) makeRequest(ctx context.Context, cfg *Config, requestID int) (string, error) {
	conn, err := newTCPConnection(cfg)
	if err != nil {
		return "", err
	}

	default:
		getTransport, closeSharedTransport = newHTTPTransportGetter(cfg)
	}

	defer closeSharedTransport()

	call := &httpCall{
		httpProtocol: c,
		getTransport: getTransport,
	}

	return doForward(ctx, cfg, c.e, call.makeRequest)
}

func newHTTP3TransportGetter(cfg *Config) (httpTransportGetter, func()) {
	newConn := func() *http3.RoundTripper {
		return &http3.RoundTripper{
			TLSClientConfig: cfg.tlsConfig,