TestWriteAfterExit fails on .NET 8

[Bartleby2718]

Explanation of the Bug

The test TestWriteAfterExit is affected by a breaking change in .NET 8: FileStream writes when pipe is closed.

Reproduction steps

1. Target net8.0 in MedallionShell.Tests.csproj and in SampleCommand.csproj
2. Run TestWriteAfterExit targeting net8.0

Full error output

 TestWriteAfterExit No source available  Duration: 158 ms

Message:  should run on current platform Expected: No Exception to be thrown But was: <System.IO.IOException: The pipe is being closed. at System.IO.RandomAccess.WriteAtOffset(SafeFileHandle handle, ReadOnlySpan`1 buffer, Int64 fileOffset) at System.IO.Strategies.OSFileStreamStrategy.Write(ReadOnlySpan`1 buffer) at System.IO.Strategies.OSFileStreamStrategy.Write(Byte[] buffer, Int32 offset, Int32 count) at System.IO.Strategies.BufferedFileStreamStrategy.Flush(Boolean flushToDisk) at Medallion.Shell.Streams.ProcessStreamWrapper.<>c.<Flush>b__22_0(Stream s, Boolean ) in //MedallionShell/Streams/ProcessStreamWrapper.cs:line 49 at Medallion.Shell.Streams.ProcessStreamWrapper.DoWriteOperation[TArg](TArg arg, Action`2 action) in //MedallionShell/Streams/ProcessStreamWrapper.cs:line 155 at Medallion.Shell.Streams.ProcessStreamWrapper.Flush() in //MedallionShell/Streams/ProcessStreamWrapper.cs:line 49 at System.IO.StreamWriter.Flush(Boolean flushStream, Boolean flushEncoder) at System.IO.StreamWriter.Write(Char[] buffer) at Medallion.Shell.Streams.ProcessStreamWriter.WriteLine() in /_/MedallionShell/Streams/ProcessStreamWriter.cs:line 294 at SampleCommand.PlatformCompatibilityTests.TestWriteAfterExit() in C:\Users\bartl\Documents\GitHub\MedallionShell\SampleCommand\PlatformCompatibilityTests.cs:line 58 at Medallion.Shell.Tests.PlatformCompatibilityTest.<>c__DisplayClass10_0.<RunTestAsync>b__0() in C:\Users\bartl\Documents\GitHub\MedallionShell\MedallionShell.Tests\PlatformCompatibilityTest.cs:line 51 at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor) at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr) --- End of stack trace from previous location --- at NUnit.Framework.Internal.ExceptionHelper.Rethrow(Exception exception) at NUnit.Framework.Internal.Reflect.DynamicInvokeWithTransparentExceptions(Delegate delegate) at NUnit.Framework.Internal.ExceptionHelper.RecordException(Delegate parameterlessDelegate, String parameterName)>

Stack Trace:  PlatformCompatibilityTest.RunTestAsync(Expression`1 testMethod) line 51 GenericAdapter`1.GetResult() AsyncToSyncAdapter.Await(Func`1 invoke) TestMethodCommand.RunTestMethod(TestExecutionContext context) TestMethodCommand.Execute(TestExecutionContext context) <>c__DisplayClass4_0.<PerformWork>b__0() <>c__DisplayClass1_0`1.<DoIsolated>b__0(Object _) 1) at Medallion.Shell.Tests.PlatformCompatibilityTest.RunTestAsync(Expression`1 testMethod) in C:\Users\bartl\Documents\GitHub\MedallionShell\MedallionShell.Tests\PlatformCompatibilityTest.cs:line 51 AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine) PlatformCompatibilityTest.RunTestAsync(Expression`1 testMethod) PlatformCompatibilityTest.TestWriteAfterExit() line 22

[madelson]

We should fix this!