socket/socket_classic.go
func LookupIP(ctx context.Context, host string) (addrs []net.IP, err error) {
	packedAddrs, _, err := resolve(ctx, ipFamilies, host)
	if err != nil {
		return nil, fmt.Errorf("socket: failed resolving %q: %v", host, err)
	}
	addrs = make([]net.IP, len(packedAddrs))
	for i, pa := range packedAddrs {
		addrs[i] = net.IP(pa)
	}
	return addrs, nil
}
func LookupIP(ctx context.Context, host string) (addrs []net.IP, err error) {
	packedAddrs, _, err := resolve(ctx, ipFamilies, host)
	if err != nil {
		return nil, fmt.Errorf("socket: failed resolving %q: %v", host, err)
	}
	addrs = make([]net.IP, len(packedAddrs))
	for i, pa := range packedAddrs {
		addrs[i] = net.IP(pa)
	}
	return addrs, nil
}
// LookupIP returns the given host's IP addresses.