How to use the sniffio.current_async_library_cvar function in sniffio

def __init__(self, library, shard_count=-1, prefixes='py.', message_cache_max=2500, **kwargs):
        super().__init__()
        sniffio.current_async_library_cvar.set(library)
        self.token = ''
        self.is_bot = True
        self._boot_up_time = None
        self.running = anyio.create_event()
        self.api = HttpClient(self)
        self.session = asks.Session()  # public session
        self.shards = [] if shard_count < 1 else list(range(shard_count))
        self.users = Collection(User)
        self.guilds = Collection(Guild)
        self.channels = Collection(Channel)
        self.messages = deque(maxlen=message_cache_max)
        self.commands = CommandCollection(self)
        self.webhooks = Collection(Webhook, indexor='name')
        self.prefixes = prefixes if isinstance(prefixes, list) else [prefixes]
        self._nonces = dict()
        self.user = None

def claim_worker_thread(backend) -> typing.Generator[Any, None, None]:
    module = sys.modules['anyio._backends._' + backend]
    _local.current_async_module = module
    token = sniffio.current_async_library_cvar.set(backend)
    try:
        yield
    finally:
        sniffio.current_async_library_cvar.reset(token)
        del _local.current_async_module