test_dask.py fails to import with distributed 2021.10.0

[risicle]

==================================== ERRORS ====================================
_________________ ERROR collecting streamz/tests/test_dask.py __________________
streamz/tests/test_dask.py:19: in <module>
    def test_map(c, s, a, b):
/nix/store/1pk6xcgl18jhk5wabzsa83r5j746ynvc-python3.8-distributed-2021.10.0/lib/python3.8/site-packages/distributed/utils_test.py:922: in _
    raise RuntimeError("gen_cluster only works for coroutine functions.")
E   RuntimeError: gen_cluster only works for coroutine functions.
=========================== short test summary info ============================

Tested with streamz 0.6.3.

dask fixed a similar issue in dask/dask@cd65507#diff-7cd4c58914fc9efc64bddea10b24254dd1e2580c7f323341340476eee24c2690

(you're likely to get a lot of people wanting to update to this distributed release pretty quickly because of https://nvd.nist.gov/vuln/detail/CVE-2021-42343)

[martindurant]

Thanks for pointing that out. It should be a simple fix, it seems, but I don't know when I will get to it. Perhaps someone else can push a PR?