Some time ago I added StopExecution method and IsCancelled flag to IHost.

It was quick solution to make certain algorithms react to stop signal from user. I doubt in long run it's proper way to do it. And it probably required lengthy discussion how to expose stopping functionality (method, or CancellationToken, or something else).

But for now I think it's a good idea to remove method and flag from our public API. Especially considering what no code actually checking IsCancelled flag.

EDIT: We decided to keep this functionality but make it internal and still be accessible via experimental nuget.