Flaky/racy test failure on .NET 10.0: DistributedCacheEventStreamStoreTests.ReadEventsAsync_InStreamingMode_YieldsNewlyWrittenEvents #1490

Summary

The CI is failing under .NET 10.0 due to a test failure in the test suite:

• Test: ModelContextProtocol.Tests.DistributedCacheEventStreamStoreTests.ReadEventsAsync_InStreamingMode_YieldsNewlyWrittenEvents

This test fails on .NET 10 while passing on earlier TFMs (net8/net9). See pipeline logs starting at:

[xUnit.net 00:01:23.69]     ModelContextProtocol.Tests.DistributedCacheEventStreamStoreTests.ReadEventsAsync_InStreamingMode_YieldsNewlyWrittenEvents [FAIL]
Failed!  - Failed:     1, Passed:  1884, Skipped:     4, Total:  1889, Duration: 3 m 19 s - ModelContextProtocol.Tests.dll (net10.0)

Most likely an intermittent failure.

Observed Behavior

• The test expects events appended after a streaming query starts to be seen via the async enumerator.
• Timing and/or notification race causes this test to fail only on net10.0.
• Other test projects and all other TFMs pass for the same code revision.

Recommendation

• Add a synchronization point so that the streaming enumerator is definitely active before appending events in the test.
• Alternatively: audit the implementation to ensure the enumerator can never miss events regardless of ordering/timing of the append.

Optional:

• Consider skipping or quarantining the test on net10.0 until race is fixed, to unblock CI.
• Clean up procdump64.exe/setup so test blame diagnostics don't obscure build logs.