ReactiveArchitecture_SavingState.java

//Save
@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putParcelable(LAST_UIMODEL, latestUiModel);
}

//Init ViewModel with saved state
public void init(@Nullable  UiModel restoredUiModel) {
    if (initialUiModel == null) {
        if (restoredUiModel == null) {
            initialUiModel = UiModel.initState();
            startEventsObservable = Observable.just(new ScrollEvent(initialUiModel.getPageNumber() + 1));
        } else {
            //restore required
            initialUiModel = UiModel.restoreState(restoredUiModel.getPageNumber(), new ArrayList<>(), null);
            startEventsObservable = Observable.just(new RestoreEvent(initialUiModel.getPageNumber()));
        }
        bind();
    }
}

/*Scan in Main Pipe*/
.scan(initialUiModel, (uiModel, result) -> {