async def METHOD_NAME(c, s, a, b):
    await c.set_metadata("locked", False)
    def f(_):
        client = get_client()
        with MultiLock(names=["x"]):
            assert client.get_metadata("locked") is False
            client.set_metadata("locked", True)
            sleep(0.05)
            assert client.get_metadata("locked") is True
            client.set_metadata("locked", False)
    futures = c.map(f, range(20))
    await c.gather(futures)
    ext = s.extensions["multi_locks"]
    assert not ext.events
    assert not ext.requests
    assert not ext.requests_left
    assert all(len(l) == 0 for l in ext.locks.values())