HTTPFileSystem prints tracebacks if skip_instance_cache=True if called more than once

I have been debugging an issue for a while and finally have a small reproducible snip. Using fsspec==2023.12.2

import fsspec

some_public_url = "http://replace.me.with.a.public.url"

def read_my_data(url: str) -> None:
    for i in range(10):
        fs = fsspec.filesystem("http", skip_instance_cache=True)
        read_data = fs.read_text(url)        
        print(i, read_data)

read_my_data(some_public_url)

The output looks something like

0
1
2
Exception ignored in: <finalize object at 0x7f644203f9e0; dead>
Traceback (most recent call last):
  File "/lib/python3.10/weakref.py", line 591, in __call__
    return info.func(*info.args, **(info.kwargs or {}))
  File "/lib/python3.10/site-packages/fsspec/implementations/http.py", line 125, in close_session
    sync(loop, session.close, timeout=0.1)
  File "/lib/python3.10/site-packages/fsspec/asyn.py", line 80, in sync
    raise NotImplementedError("Calling sync() from within a running loop")
NotImplementedError: Calling sync() from within a running loop
Exception ignored in: <finalize object at 0x7f644203fae0; dead>
Traceback (most recent call last):
  File "/python3.10/weakref.py", line 591, in __call__
    return info.func(*info.args, **(info.kwargs or {}))
  File "/lib/python3.10/site-packages/fsspec/implementations/http.py", line 125, in close_session
    sync(loop, session.close, timeout=0.1)
  File "/python3.10/site-packages/fsspec/asyn.py", line 80, in sync
    raise NotImplementedError("Calling sync() from within a running loop")
NotImplementedError: Calling sync() from within a running loop
Unclosed client session
client_session: <aiohttp.client.ClientSession object at 0x7f644207e2f0>
Unclosed client session
client_session: <aiohttp.client.ClientSession object at 0x7f644207ee90>
3
4
5
done

The number of successes before this is error is printed is not consistent but usually after 2 or 3. This traceback is not fatal and the correct data is read but this is an ugly traceback to be printed which I do not know how to suppress.

If instead skip_instance_cache=False I do not see this issue. My guess is something wrong is cached internally between runs?

Start with the repeated skip_instance_cache=True reproducer and inspect fsspec/implementations/http.py around close_session and fsspec/asyn.py around sync, as identified in the traceback. Check the related finalization and session lifecycle behavior; done means repeated HTTPFileSystem use no longer prints tracebacks or unclosed-session warnings while still reading the data.