How to use the avro.datafile.DataFileReader function in avro

parser.add_argument('avro_file', help='Avro file for iterate')
    parser.add_argument('--pyavro', default=False, action='store_true',
                        help='run the avro python benchmark as well')

    args = parser.parse_args(argv[1:])

    from fastavro import reader
    print('Using {0}'.format(reader))
    with open(args.avro_file, 'rb') as fo:
        timeit('fastavro', reader(fo))

    if args.pyavro:
        import avro.io
        import avro.datafile
        with open(args.avro_file, 'rb') as fo:
            reader = avro.datafile.DataFileReader(fo, avro.io.DatumReader())
            timeit('avro', reader)

def read_avro(fin):
    reader = avro.datafile.DataFileReader(fin, avro.io.DatumReader())
    return list(reader)

def _read_avro(fhandle, path, offset, length, stats):
    contents = ''
    try:
        fhandle.seek(offset)
        data_file_reader = datafile.DataFileReader(fhandle, io.DatumReader())

        try:
            contents_list = []
            read_start = fhandle.tell()
            # Iterate over the entire sought file.
            for datum in data_file_reader:
                read_length = fhandle.tell() - read_start
                if read_length > length and len(contents_list) > 0:
                    break
                else:
                    datum_str = str(datum) + "\n"
                    contents_list.append(datum_str)
        finally:
            data_file_reader.close()

        contents = "".join(contents_list)

if _format in {'XLS', 'XLSX'}:
        for line in read_xls(_file):
            yield line
    else:
        mode = 'r' if _format != 'AVRO' else 'rb'
        with open(_file, mode) as data:
            # preformatting on all data
            if 'TAIL' in _format:
                update_state('current_file', json.dumps({st_ino: _file}))
                data.seek(int(agent_config_vars['state']['current_file_offset'])) # read from state
            if _format == 'XML':
                data = xml2dict.parse(data)
                yield data
            else:
                if _format == 'AVRO':
                    data = avro.datafile.DataFileReader(data, avro.io.DatumReader())
                # read each line
                logger.debug('reading each line')
                for line in data:
                    yield reader_next_line(_format, data, line)
                if 'TAIL' in _format:
                    if 'TAILF' in _format:
                        logger.debug('tailing file')
                        # keep reading file
                        for line2 in tail_file(_file, data):
                            yield reader_next_line(_format, data, line2)
                        # move from current file to completed, reset position
                        update_state('completed_files_st_ino', st_ino, append=True)
                        update_state('current_file', '')
                        update_state('current_file_offset', 0)