Usage of `weakref.finalize` causes `RuntimeError: Loop is not running`

import pytest
from adlfs import AzureBlobFileSystem


@pytest.fixture()
def fs():
    return AzureBlobFileSystem(..., asynchronous=True)


@pytest.mark.asyncio
async def test_something(fs: AzureBlobFileSystem):
    pass

A simple setup like this, where the fs is created within an async context (event loop will be set up by pytest-asyncio here), will result in a RuntimeError: Loop is not running during gc.

This is caused by these lines:

https://github.com/fsspec/adlfs/blob/adb9c53b74a0d420625b86dd00fbe615b43201d2/adlfs/spec.py#L346-L349

which obtain a reference to the current event loop, however, since there's no guarantee when finalization on the refs will run, this can also happen after the referenced event loop has been closed.

Since all they're doing is closing things, I would like to propose adding a close method to the implementation, which can be manually invoked to do proper cleanup, and a conditional check on the finalizers, so they may not run if the resources have already been closed.

Then, all that's needed in the code to fix the issue is something like

@pytest.fixture()
async def fs():
    fs = AzureBlobFileSystem(..., asynchronous=True)
    yield fs
    await fs.close()

Start in adlfs/spec.py around lines 346-349 and trace how weakref.finalize obtains and uses the event loop. Review the issue's proposed explicit close flow and fixture example. Done means resources can be closed explicitly and garbage-collection finalization does not raise RuntimeError after the loop has closed.