netaddress.go
func (na *NetAddress) Valid() bool {
	return na.IP != nil && !(na.IP.IsUnspecified() || na.RFC3849() ||
		na.IP.Equal(net.IPv4bcast))
}
func (na *NetAddress) Valid() bool {
	return na.IP != nil && !(na.IP.IsUnspecified() || na.RFC3849() ||
		na.IP.Equal(net.IPv4bcast))
}
// For IPv4 these are either a 0 or all bits set address. For IPv6 a zero
// address or one that matches the RFC3849 documentation address format.