here's a reproducer:

import gc
import tornado.web
import tornado.httpclient
import asyncio
import contextlib


def make_handler(cb):
    class MainHandler(tornado.web.RequestHandler):
        async def get(self):
            cb()
            self.write("hello")
            await asyncio.Event().wait()

    return MainHandler


async def run_webserver(cb):
    application = tornado.web.Application([(r"/", make_handler(cb))])
    server = application.listen(8888)
    try:
        await asyncio.Event().wait()
    finally:
        await server.close_all_connections()


async def make_request():
    with contextlib.closing(
        tornado.httpclient.AsyncHTTPClient(force_instance=True)
    ) as client:
        await client.fetch("http://localhost:8888/")


async def garbage_collect_on_request(event, done):
    await event.wait()
    gc.collect()
    done()


async def main():
    event = asyncio.Event()

    class Result(Exception):
        pass

    def done():
        raise Result()

    try:
        await asyncio.gather(
            run_webserver(event.set),
            make_request(),
            garbage_collect_on_request(event, done),
        )
    except Result:
        pass


asyncio.run(main())

note the note on https://docs.python.org/3/library/asyncio-task.html#asyncio.create_task

Important: Save a reference to the result of this function, to avoid a task disappearing mid-execution. The event loop only keeps weak references to tasks. A task that isn’t referenced elsewhere may get garbage collected at any time, even before it’s done. For reliable “fire-and-forget” background tasks, gather them in a collection

avoid calls to make_current() and make_clear() by using asyncio.run in LoopRunner

Closes #6784

Various cleanups in semaphore (#5885)

avoid calls to make_current() and make_clear() by using asyncio.run in LoopRunner

Closes #6784

Set lifetime-stagger default value to None (#7445)

avoid calls to make_current() and make_clear() by using asyncio.run in LoopRunner

Closes #6784

avoid calls to make_current() and make_clear() by using asyncio.run in LoopRunner

Closes #6784

avoid calls to make_current() and make_clear() by using asyncio.run in LoopRunner

Closes #6784

Closes #6784

• [ ] Tests added / passed
• [ ] Passes pre-commit run --all-files

avoid calls to make_current() and make_clear() by using asyncio.run in LoopRunner

Closes #6784

Zooming back a bit, why is this change needed? From skimming the PEP, it looks like it's for improved Windows support. Is that the case? Are there other reasons?

There's an unfortunate bit of noise in the tests, but the main advantage is being able to load the dask config file containing special characters on a platform with encoding not set to UTF-8 (eg some docker containers), and detecting new code that is introduced that is not explicit about the encoding because the python default behaviour is set to change in the future.

yaml and json both support auto-detecting the encoding of the passed in file, but only if the file is opened in bytes mode - opening the file in text mode bypasses that feature.

regarding the SRI files omitting the encoding kwarg may be a false positive of PEP 597 it still throws the warning on import for downstream projects.

I could have passed encoding="ascii" here, but opening the the json file in bytes mode also supports auto-detecting the encoding so I opted for that

yeah that's the reference I had in mind:

when you open a yaml file with rb yaml can auto-detect the encoding:

>>> with open("example.yaml", "w", encoding="utf-16") as f:
...     yaml.dump({}, f)
... 
>>> with open("example.yaml", "rb") as f:
...     yaml.safe_load(f)
... 
{}

but if you use the "locale" encoding the determine_encoding feature doesn't work:

>>> with open("example.yaml") as f:
...     yaml.safe_load(f)
... 
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "/home/graingert/.virtualenvs/testing311/lib/python3.11/site-packages/yaml/__init__.py", line 125, in safe_load
    return load(stream, SafeLoader)
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/graingert/.virtualenvs/testing311/lib/python3.11/site-packages/yaml/__init__.py", line 79, in load
    loader = Loader(stream)
             ^^^^^^^^^^^^^^
  File "/home/graingert/.virtualenvs/testing311/lib/python3.11/site-packages/yaml/loader.py", line 34, in __init__
    Reader.__init__(self, stream)
  File "/home/graingert/.virtualenvs/testing311/lib/python3.11/site-packages/yaml/reader.py", line 85, in __init__
    self.determine_encoding()
  File "/home/graingert/.virtualenvs/testing311/lib/python3.11/site-packages/yaml/reader.py", line 124, in determine_encoding
    self.update_raw()
  File "/home/graingert/.virtualenvs/testing311/lib/python3.11/site-packages/yaml/reader.py", line 178, in update_raw
    data = self.stream.read(size)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen codecs>", line 322, in decode
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 0: invalid start byte