Saving With RxJava and the Repository Pattern

Hi, I have been reading the other issues and they all seem to be related to data retrieval rather than saving data. Both `UseCase`s in the project are for retrieval also.

My question is:

_What should I return (if anything) upon saving an entity and should this be an `Observable`?_

At the moment, following the whole separation of concerns and mapping entities at boundaries we get:

`UserModel > User > UserEntity - (save in repo) - (return saved entity) - UserEntity > User > UserModel`

Is this correct or is there a different pattern I should be following for `insert` and `update` operations?