Use of Schedulers on UseCase

Hi,

I was reading your project and there's something regarding the use of Schedulers on UseCase that I don't well understand.

Note that I'm quite new to android programming so please forgive me if I say something terribly wrong! 😅

So, why the UseCase needs a ThreadExecutor for the "backend" computation and a Scheduler to execute the observer? Why not ask for the same type?

I mean, if the reason to ask for a ThreadExecutor is to be free to use whatever executor you want, why the same thing doesn't apply for `observeOn`? Why can't we ask again for another ThreadExecutor and simply call `observeOn(Schedulers.from(executor))`?
(Note: I understand that is very simple to refer to the main thread using Schedulers thanks to `AndroidSchedulers.mainThread()`. There isn't a so simple way to obtain the main ThreadExecutor on Android?)

And why we can't achieve the same result asking for two Schedulers?
I mean, if I want simply use Schedulers.io() as background scheduler, how can I pass it to the UseCase?
If the UseCase was asking for a Scheduler also for `subscribeOn`, I could pass Schedulers.io() or a custom scheduler (created with `Scheduler.from(myThreadExecutor)`) based on my need.

Thanks in advance!

Nell’issue non viene identificato alcun file o test. Inizia individuando l’implementazione di UseCase e il suo utilizzo di ThreadExecutor, subscribeOn, observeOn e Scheduler; il lavoro sarebbe completato con una spiegazione concordata o una modifica alla documentazione che chiarisca perché queste astrazioni differiscono e come fornire scheduler personalizzati.

Scritto dal modello di indicizzazione a partire dal testo della issue.