Thing.kt

public LiveData<Resource<PlaylistContents>> observePlaylistData(String id) {
        if (playlistContentsLiveData == null) {
            playlistContentsLiveData = new MutableLiveData<>();

            playlistContentsLiveData.postValue(Resource.loading((PlaylistContents) null));

            apiService.getPlaylistContents(CharParser.removeEmptySpaces(id))
                    .subscribeOn(Schedulers.io())
                    .subscribe(data -> playlistContentsLiveData.postValue(Resource.success(data)),
                            e -> playlistContentsLiveData.postValue(Resource.error(e.getMessage(), (PlaylistContents) null)));

        }

        return playlistContentsLiveData;
    }