[QUIC] SendMoreThanStreamLimitRequestsConcurrently_LastWaits on Mocks hangs in CI

[ManickaP]

SocketsHttpHandlerTest_Http3_Mock.SendMoreThanStreamLimitRequestsConcurrently_LastWaits(10) will regularly hang in CI.
Discovered in #52704.

I'm unable to reproduce locally, even with the test running in a loop for more than an hour.

Test is disable via a condition in code:

// This combination leads to a hang manifesting in CI only. Disabling it until there's more time to investigate.
if (this.UseQuicImplementationProvider == QuicImplementationProviders.Mock)
{
    return;
}

Update: Seems like the first run of this tends to timeout (now it's the 100), disabling all mock runs for now.

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Issue Details

---

SocketsHttpHandlerTest_Http3_Mock.SendMoreThanStreamLimitRequestsConcurrently_LastWaits(10) will regularly hang in CI.
Discovered in #52704.

I'm unable to reproduce locally, even with the test running in a loop for more than an hour.

Test is disable via a condition in code:

// This combination leads to a hang manifesting in CI only. Disabling it until there's more time to investigate.
if (streamLimit == 10 && this.UseQuicImplementationProvider == QuicImplementationProviders.Mock)
{
    return;
}

Author:	ManickaP
Assignees:	-
Labels:	area-System.Net.Quic, disabled-test
Milestone:	-

[radical]

Is this failure caused by the problem being tracked here? (linux x64)
Log
Build

System.Net.Http.Functional.Tests.SocketsHttpHandlerTest_Http3_MsQuic.SendMoreThanStreamLimitRequestsConcurrently_LastWaits(streamLimit: 10) [FAIL]
      System.TimeoutException : The operation has timed out.
      Stack Trace:
        /_/src/libraries/Common/tests/System/Threading/Tasks/TaskTimeoutExtensions.cs(49,0): at System.Threading.Tasks.TaskTimeoutExtensions.WhenAllOrAnyFailed(Task[] tasks, Int32 millisecondsTimeout)
        /_/src/libraries/System.Net.Http/tests/FunctionalTests/HttpClientHandlerTest.Http3.cs(273,0): at System.Net.Http.Functional.Tests.HttpClientHandlerTest_Http3.SendMoreThanStreamLimitRequestsConcurrently_LastWaits(Int32 streamLimit)
        --- End of stack trace from previous location ---

[ManickaP]

I spun up a new issue.

[ManickaP]

#70421