GetRequest_Receives_UnsolicitedNotifications is hanging in CI #1211
Description
Tests are hanging and hitting the 7 minute test runner timeout. The dumps show the following task is hanging.
<< Awaiting: 00007ee35e6b42f8 00007f2378dd04e0 System.Runtime.CompilerServices.ValueTaskAwaiter<System.Boolean> >>
00007ee35e6b49e0 00007f237c4703d8 (0) ModelContextProtocol.AspNetCore.Tests.StreamableHttpServerConformanceTests+<>c__DisplayClass22_0+<<GetRequest_Receives_UnsolicitedNotifications>g__GetFirstNotificationAsync|1>d
00007ee35e699fb8 00007f237c454da0 (4) ModelContextProtocol.AspNetCore.Tests.StreamableHttpServerConformanceTests+<GetRequest_Receives_UnsolicitedNotifications>d__22
00007ee35e69a008 00007f237aeee0f8 (0) Xunit.v3.TestRunner<Xunit.v3.XunitTestRunnerContext, Xunit.v3.IXunitTest>+<>c__DisplayClass5_0+<<InvokeTest>b__1>d
00007ee35e69a078 00007f237aeee4b0 (0) Xunit.v3.ExceptionAggregator+<RunAsync>d__13
00007ee35e69a0f0 00007f237aeee980 (0) Xunit.v3.ExecutionTimer+<MeasureAsync>d__2
00007ee35e69a170 00007f237aef8558 (0) Xunit.v3.ExceptionAggregator+<RunAsync>d__14<System.TimeSpan>
00007ee35e69a200 00007f237aef9260 (0) Xunit.v3.TestRunner<Xunit.v3.XunitTestRunnerContext, Xunit.v3.IXunitTest>+<>c__DisplayClass15_1+<<RunTest>g__runTest|0>d
Originally posted by @ericstj in #1210 (comment)