Inconsistent behavior in HttpContext.RequestAborted.IsCancellationRequested

[avparuch]

Describe the bug

When a client disconnects, I expect HttpContext.RequestAborted.IsCancellationRequested to return true. On Kestrel, this is indeed the case. However on HttpSysServer, HttpContext.RequestAborted.IsCancellationRequested returns false despite the client disconnecting.

To Reproduce

1. Fire up any Kestrel sample project in Visual Studio: https://github.com/dotnet/AspNetCore.Docs/tree/main/aspnetcore/fundamentals/servers/kestrel/samples/5.x/KestrelSample

2. Fire up any HttpSysServer sample project in Visual Studio: https://github.com/dotnet/AspNetCore.Docs/tree/main/aspnetcore/fundamentals/servers/httpsys/samples/3.x/SampleApp

3. Send requests to both servers and abruptly disconnect your client. I've attached a simple TCPClient I used.
   TCPClient.zip

4. HttpContext.RequestAborted.IsCancellationRequested returns true on Kestrel, returns false on HttpSysServer.

Further technical details

• ASP.NET Core version : 5.0.9

[Tratcher]

Duplicate of #17278