func mustParseIPAddr(str string) net.Addr {
	a, err := net.ResolveIPAddr("ip", str)
	if err != nil {
		panic("mustParseIPAddr")
	}
	return a
}
func mustParseIPNet(str string) net.Addr {
	_, n, err := netutils.ParseCIDRSloppy(str)
	if err != nil {
		panic("mustParseIPNet")
	}
	return n
}
func mustParseUnix(str string) net.Addr {
	n, err := net.ResolveUnixAddr("unix", str)
	if err != nil {
		panic("mustParseUnix")