Hotloading: Async method marked as completed too early

[DevulTj]

Describe the bug

I noticed it if you hotload sometimes (it's not 100%, but if you spam save on a file a few times you'll notice it on an empty project)

To Reproduce

1. Open attached project
2. Open in play mode
3. Notice "Before Test" text in the console
4. If you hotload a few times, you will notice "After Test" will run before the 30 seconds timer is up.

Expected behavior

Should maintain state

Media/Files

async_hotloading_test.zip

Additional context

No response

[DevulTj]

I'm also gonna note here that the same issue seems to happen when performing host migration - which makes sense. I've not looked too much into it though, I don't see how we'd make it work really.

[Metapyziks]

Thanks for the repro. Looks like Time.Now jumps occasionally, maybe Task.DelayInternal() continues in the wrong Time.Scope().

[Metapyziks]

Yeah we're pumping the main thread sync context continuation queue at a few points during hotload.

I think this is exposing a bigger problem, there will be continuations in there for both editor and game tasks, with different scene and / or time scopes. Either we should have separate SyncContexts for editor vs game, or capture things like the active scene when posting to a sync context. I'm going to mock up the latter because it should be a smaller change.