Read an entire "mysql packet" in its entirety from the network
        and return a MysqlPacket type that represents the results.

        :raise OperationalError: If the connection to the MySQL server is lost.
        :raise InternalError: If the packet sequence number is wrong.

def _read_packet(self, packet_type=MysqlPacket):
        """Read an entire "mysql packet" in its entirety from the network
        and return a MysqlPacket type that represents the results.

        :raise OperationalError: If the connection to the MySQL server is lost.
        :raise InternalError: If the packet sequence number is wrong.
        """
        buff = bytearray()
        while True:
            packet_header = self._read_bytes(4)
            #if DEBUG: dump_packet(packet_header)

            btrl, btrh, packet_number = struct.unpack('<HBB', packet_header)
            bytes_to_read = btrl + (btrh << 16)
            if packet_number != self._next_seq_id:
                self._force_close()
                if packet_number == 0:
                    # MariaDB sends error packet with seqno==0 when shutdown
                    raise err.OperationalError(
                        CR.CR_SERVER_LOST,
                        "Lost connection to MySQL server during query")
                raise err.InternalError(
                    "Packet sequence number wrong - got %d expected %d"
                    % (packet_number, self._next_seq_id))
            self._next_seq_id = (self._next_seq_id + 1) % 256

            recv_data = self._read_bytes(bytes_to_read)
            if DEBUG: dump_packet(recv_data)
            buff += recv_data
            # https://dev.mysql.com/doc/internals/en/sending-more-than-16mbyte.html
            if bytes_to_read == 0xffffff:
                continue
            if bytes_to_read < MAX_PACKET_LEN:
                break

        packet = packet_type(bytes(buff), self.encoding)
        packet.check_error()
        return packet