@Inject lateinit var sessionDetailViewModelFactory: SessionDetailViewModel.Factory
private val sessionDetailViewModel by assistedViewModels {
    sessionDetailViewModelFactory.create(navArgs.sessionId)
}

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)
    ...
    sessionDetailViewModel.uiModel
        .observe(viewLifecycleOwner) { uiModel: SessionDetailViewModel.UiModel ->
            ...
            progressTimeLatch.loading = uiModel.isLoading
            uiModel.session
                ?.let { session -> setupSessionViews(session) }
        }
    }

class SessionsViewModel @Inject constructor(
    val sessionRepository: SessionRepository
) : ViewModel() {

...
    private val sessionLoadState: LiveData<LoadState<SessionContents>> = liveData {
        emitSource(
            sessionRepository.sessionContents()
                .toLoadingState()
                .asLiveData()
        )
        sessionRepository.refresh()
    }

class SessionDetailViewModel @AssistedInject constructor(
    @Assisted private val sessionId: SessionId,
    private val sessionRepository: SessionRepository
) : ViewModel() {
...
    val uiModel: LiveData<UiModel> = combine(
        initialValue = UiModel.EMPTY,
        liveData1 = sessionLoadStateLiveData,
        liveData2 = favoriteLoadingStateLiveData
    ) { current: UiModel,
        sessionLoadState: LoadState<Session>,
        favoriteState: LoadingState ->
        // You can create loading state by multiple LiveData
        val isLoading = sessionLoadState.isLoading || favoriteState.isLoading
        UiModel(
            isLoading = isLoading,
            error = sessionLoadState
                .getErrorIfExists()
                .toAppError()
                ?: favoriteState
                    .getErrorIfExists()
                    .toAppError()
            ,
            session = sessionLoadState.value
        )
    }

class SessionDetailViewModel @AssistedInject constructor(
    @Assisted private val sessionId: SessionId,
    private val sessionRepository: SessionRepository
) : ViewModel() {
..
    private var favoriteLoadingStateLiveData: MutableLiveData<LoadingState> = MutableLiveData(LoadingState.Loaded)
...
    fun favorite(session: Session) {
        viewModelScope.launch {
            favoriteLoadingStateLiveData.value = LoadingState.Loading
            try {
                sessionRepository.toggleFavoriteWithWorker(session.id)
                favoriteLoadingStateLiveData.value = LoadingState.Loaded
            } catch (e: Exception) {
                favoriteLoadingStateLiveData.value = LoadingState.Error(e)
            }
        }
    }