Encapsulates an Arp Packet and provides the mechanisms to generate new Arp Packets. This is immutable.
The Header is of the format: FieldPositionHardware Type2 BytesProtocol Type2 BytesHardware Length1 ByteProtocol Length1 ByteOperation2 BytesSender HW AddressHW LengthSender Proto AddressProto LengthTarget HW AddressHW LengthTarget Proto AddressProto Length