'Return request_id, data, max_doc_size.
:Parameters:
- `message`: (request_id, data, max_doc_size) or (request_id, data)'

def _split_message(self, message):

    if (len(message) == 3):
        return message
    else:
        (request_id, data) = message
        return (request_id, data, 0)
