Generates the first (IKE_INIT) packet for Initiator

        :return: bytes() containing a valid IKE_INIT packet

def init_send(self):
        """
        Generates the first (IKE_INIT) packet for Initiator

        :return: bytes() containing a valid IKE_INIT packet
        """
        packet = Packet()
        self.packets.append(packet)
        packet.add_payload(payloads.SA())
        packet.add_payload(payloads.KE(diffie_hellman=self.diffie_hellman))
        packet.add_payload(payloads.Nonce(nonce=self.Ni))
        packet.iSPI = self.iSPI = packet.payloads[0].spi
        self.state = State.INIT
        return bytes(packet)