MaximSagan

I think what we need is something like [rx-js traits](https://github.com/cartant/rxjs-traits) (developed by rxjs core team members). If we had a guarantee that an observable would be synchronous (which, in rxjs-traits...

> If we did have that, and async did emit null, even if it was "confidently", we would actually still have the problem I'm describing in he child components. I...

> RxJS Traits sounds really interesting! But I don't think that Angular would lean on them unless they were part of the official RxJS package. Yep, just brought it up...

> Beside my other comments, We'll like this feature change to be covered by the corresponding unit tests in `packages/common/test/directives/ng_component_outlet_spec.ts`. > > You'll be able to run the unit tests...

> Indeed for some technical reasons, you can't use the initializer APIs (input, output, signal view queries) in the unit tests. We're fine with decorators here. Got it, updated to...

@JeanMeche @crisbeto Could I get a review on this? Also, not sure how to trigger test pipeline.