ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
	defer cancel()
	var addrs []netip.Addr
	var lookupErr error
	if (len(lookupIPAddr) > 0) && (lookupIPAddr[0] != nil) {
		// if there are more than one lookup function, ignore all but first
		addrs, lookupErr = lookupIPAddr[0](ctx, host)
	} else {
		addrs, lookupErr = net.DefaultResolver.LookupNetIP(ctx, "ip", host)
	}
	if lookupErr != nil || len(addrs) == 0 {

	return &url.URL{Scheme: schemeReq, Host: net.JoinHostPort(info.Hostname, portReq)}, proxyTransport, nil
}

func isProxyableHostname(ctx context.Context, hostname string) error {
	resp, err := net.DefaultResolver.LookupIPAddr(ctx, hostname)
	if err != nil {
		return err
	}

	if len(resp) == 0 {
		return fmt.Errorf("no addresses for hostname")
	}
	for _, host := range resp {
		if !host.IP.IsGlobalUnicast() {

		default:
			panic("unexpected network: " + net)
		}
	}
	if host == "" {
		return addrList{inetaddr(IPAddr{})}, nil
	}

	// Try as a literal IP address, then as a DNS name.
	ips, err := r.lookupIPAddr(ctx, net, host)
	if err != nil {
		return nil, err
	}
	// Issue 18806: if the machine has halfway configured
	// IPv6 such that it can bind on "::" (IPv6unspecified)