private UdpHeader createTemplate(UdpHeader header) {
        UdpHeader templateUdp = header.copy();
        IpHeader templateIp = templateUdp.getIpHeader();
        // Swap ip
        int sourceIp = templateIp.getSourceIp();
        int destinationIp = templateIp.getDestinationIp();
        templateIp.setSourceIp(destinationIp);
        templateIp.setDestinationIp(sourceIp);
        // Swap port
        short sourcePort = templateUdp.getSourcePort();
        short destinationPort = templateUdp.getDestinationPort();
        templateUdp.setDestinationPort(sourcePort);
        templateUdp.setSourcePort(destinationPort);
        return templateUdp;
    }
UDP protocol virtual gateway tunnel wraps {@link UdpRemoteTunnel} and itself as client and
server.

@author Megatron King
@since 2018-11-25 20:16
netbare-core/src/main/java/com/github/megatronking/netbare/tunnel/UdpVATunnel.java