helper function for put
    :param filename: <str>
    :param content: <bytes>
    :param conn: <rethinkdb.DefaultConnection>
    :return: <dict>

def put_buffer(filename, content, conn=None):
    """
    helper function for put
    :param filename: <str>
    :param content: <bytes>
    :param conn: <rethinkdb.DefaultConnection>
    :return: <dict>
    """
    obj_dict = {PRIMARY_FIELD: filename,
                CONTENT_FIELD: content,
                TIMESTAMP_FIELD: time()}
    return put(obj_dict, conn=conn)