IcmpV4EchoPacket.Builder b = new IcmpV4EchoPacket.Builder();
b.identifier(identifier)
.sequenceNumber(sequenceNumber)
.payloadBuilder(unknownb);
IcmpV4EchoPacket packet = b.build();
IcmpV4CommonPacket.Builder icmpV4b = new IcmpV4CommonPacket.Builder();
icmpV4b.type(IcmpV4Type.ECHO)
.code(IcmpV4Code.NO_CODE)
.payloadBuilder(new SimpleBuilder(packet))