code: def _gen_header(self, sequence, payloadtype):
          
          protocol = bytearray.fromhex("00 34")
          source = bytearray.fromhex("42 52 4b 52")
          target = bytearray.fromhex("00 00 00 00 00 00 00 00")
          reserved1 = bytearray.fromhex("00 00 00 00 00 00")
          sequence = pack("<B", sequence)
          ack = pack(">B", 3)
          reserved2 = bytearray.fromhex("00 00 00 00 00 00 00 00")
          packet_type = pack("<H", payloadtype)
          reserved3 = bytearray.fromhex("00 00")
  
          # assemble header
          header = bytearray(protocol)
          header.extend(source)
          header.extend(target)
          header.extend(reserved1)
          header.extend(ack)
          header.extend(sequence)
          header.extend(reserved2)
          header.extend(packet_type)
          header.extend(reserved3)
  
          return header
docs: Create packet header.