Documentation/references for internals of Blazor host stopping

[macias]

Background: I write Blazor Server app and I am concerned with the time it takes to get from "host stopping" to "host stopped".

I am not asking in sense "please help me fix my current app", I am asking for general directions what could I read, what could I check, where could I inject something to understand what is going on when host is stopping.

The only thing I figured out so far, that if there is no page opened for my service, the stopping is almost immediate. But this kind of checking is not effective.

Update: so far I found setting shutdown timeout on builder services:

        services.Configure<HostOptions>(options =>
        {
            options.ShutdownTimeout = TimeSpan.Zero;
        });

reduces stop time to 5 seconds. This is still not zero though.