After fresh update and debug rebuild on master(3.7), with Win10 patched last night, I got
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FAIL: test_call_later (test.test_asyncio.test_events.ProactorEventLoopTests)
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Traceback (most recent call last):
File "F:\dev\3x\lib\test\test_asyncio\test_events.py", line 290, in test_call_later
self.assertTrue(0.08 <= t1-t0 <= 0.8, t1-t0)
AssertionError: False is not true : 0.07800000000861473
I have not seen this before. Four subsequent runs passed.