ReactiveArchiteture_NowPlayingActivity_OldManListener.java

compositeDisposable.add(nowPlayingViewModel.getUiModels()
    .subscribe(this::processUiModel, 
               throwable -> { throw new UnsupportedOperationException("Errors from Model Unsupported: ");}
    )
);

private void processUiModel(UiModel uiModel) {        
    this.latestUiModel = uiModel;

    //Update progressBar...
       
    //Update adapter
       
    //Error Messages
}