Generate "keys" for encoded lists in the sequence
    b"0\x00", b"1\x00", b"2\x00", ...

    The first 1000 keys are returned from a pre-built cache. All
    subsequent keys are generated on the fly.

def gen_list_name():
    """Generate "keys" for encoded lists in the sequence
    b"0\x00", b"1\x00", b"2\x00", ...

    The first 1000 keys are returned from a pre-built cache. All
    subsequent keys are generated on the fly.
    """
    for name in _LIST_NAMES:
        yield name

    counter = itertools.count(1000)
    while True:
        yield b(str(next(counter))) + b"\x00"