Test failure WaiterRemovedAfterDispose

[amcasey]

Microsoft.Extensions.Time.Testing.Test.TimerTests.WaiterRemovedAfterDispose

Assert.Equal() Failure: Values differ
Expected: 2
Actual:   1

   at Microsoft.Extensions.Time.Testing.Test.TimerTests.WaiterRemovedAfterDispose() in D:\a\_work\1\s\test\Libraries\Microsoft.Extensions.TimeProvider.Testing.Tests\TimerTests.cs:line 237

https://dev.azure.com/dnceng-public/public/_build/results?buildId=818533

[amcasey]

FYI @RussKie - last time you wanted to investigate, rather than skip

[amcasey]

https://dev.azure.com/dnceng-public/public/_build/results?buildId=819061 too

[RussKie]

@dotnet/dotnet-extensions-fundamentals please triage

[amadeuszl]

I'm checking this one, verifying it's a problem with test itself or the actual logic. Can't assign the issue to myself yet due to lack of permissions.

[amadeuszl]

To me it sounds like it could be problem with resource utilization on the agent running the build and unexpected behavior on memory or GC.
There're 2 options I see so far:

1. Callback gets removed
2. Second Timer is removed from Provider

For 1st point I'm not really sure how to look for more details. But for second we can exclude it if we check waitersCountAfter first, to see if provider still has a timer. I will issue PR for that.

[amadeuszl]

I'll be checking pipelines from time to time, but let me know in case there's new failure.