Setting the loop attribute is now broken on newer versions of fsspec

[isidentical]

Please see fsspec/filesystem_spec#572 for details but simply the problem is loop on AsyncFileSystem is now a property without a setter so adlfs can't simply set it (reproducer would be just caling AzureBlobFileSystem()) and fails wit the following error;

    def __init__(
        self,
        account_name: str = None,
        account_key: str = None,
        connection_string: str = None,
        credential: str = None,
        sas_token: str = None,
        request_session=None,
        socket_timeout: int = None,
        blocksize: int = create_configuration(storage_sdk="blob").max_block_size,
        client_id: str = None,
        client_secret: str = None,
        tenant_id: str = None,
        loop=None,
        asynchronous: bool = False,
        default_fill_cache: bool = True,
        default_cache_type: str = "bytes",
        **kwargs,
    ):
        super_kwargs = {
            k: kwargs.pop(k)
            for k in ["use_listings_cache", "listings_expiry_time", "max_paths"]
            if k in kwargs
        }  # pass on to fsspec superclass
        super().__init__(asynchronous=asynchronous, **super_kwargs)
        self.account_name = account_name or os.getenv("AZURE_STORAGE_ACCOUNT_NAME")
        self.account_key = account_key or os.getenv("AZURE_STORAGE_ACCOUNT_KEY")
        self.connection_string = connection_string or os.getenv(
            "AZURE_STORAGE_CONNECTION_STRING"
        )
        self.sas_token = sas_token or os.getenv("AZURE_STORAGE_SAS_TOKEN")
        self.client_id = client_id or os.getenv("AZURE_STORAGE_CLIENT_ID")
        self.client_secret = client_secret or os.getenv("AZURE_STORAGE_CLIENT_SECRET")
        self.tenant_id = tenant_id or os.getenv("AZURE_STORAGE_TENANT_ID")
        self.credential = credential
        self.request_session = request_session
        self.socket_timeout = socket_timeout
        self.blocksize = blocksize
>       self.loop = loop or get_loop()
E       AttributeError: can't set attribute

/home/isidentical/.venv38/lib/python3.8/site-packages/adlfs/spec.py:388: AttributeError

[hayesgb]

Does this need to be pinned to a specific version of fsspec, or is it backward compatible?

[isidentical]

It is always good to fix dependencies, though I think my patch should work on all versions