private int
maxUDPSize(Message query) {
	OPTRecord opt = query.getOPT();
	if (opt == null)
		return DEFAULT_UDPSIZE;
	else
		return opt.getPayloadSize();
}
Sets the local address to bind to when sending messages.  A random port
will be used.
@param addr The local address to send messages from.
src/main/java/core/org/xbill/DNS/SimpleResolver.java