def get_first_message_bytes(self, num):
        if self._msg_start < 0:
            raise IndexError(
                'buffer was compacted but message boundaries not reset')
        if num > self._msg_length:
            num = self._msg_length
        return self._buffer[self._msg_start:self._msg_start + num]
Get up until num bytes from the beginning of the message.
dataset/ETHPy150Open rlenglet/openfaucet/src/openfaucet/buffer.py/ReceiveBuffer.get_first_message_bytes