DRAFT: deprecate awaiting objects that need an async context manager

[graingert]

Closes #xxxx

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

very drafty experiment just to see what breaks see also:

• https://github.com/dask/distributed/issues/6785
• https://github.com/dask/distributed/issues/6201

await Client() can be done by doing something like:

def create_client(*, task_status):
    async with Client(...) as client:
        task_status.started(client)
        await sleep_forever()

async with create_task_group() as tg:
    client = await tg.start(create_client)

[github-actions[bot]]

Unit Test Results

See test report for an extended history of previous test failures. This is useful for diagnosing flaky tests.

       15 files  ±  0         15 suites  ±0   6h 45m 42s :stopwatch: + 22m 50s   3 007 tests +  2    2 922 :heavy_check_mark: ±0    84 :zzz: +  2  1 :x: ±0  22 255 runs  +16  21 273 :heavy_check_mark: +2  981 :zzz: +14  1 :x: ±0 

For more details on these failures, see this check.

Results for commit 0a86d436. ± Comparison against base commit a1d2011e.

:recycle: This comment has been updated with latest results.