GoogleVisionActivity.kt

    private lateinit var mViewModel: CloudAutoMLViewModel

    override fun onCreate(icicle: Bundle?) {
        super.onCreate(icicle)

        mViewModel = ViewModelProviders.of(this).get(CloudAutoMLViewModel::class.java)
        mViewModel.subscribeClassifications()
            .observe(this, Observer<Resource<Pair<Int, String>, Throwable>> { resource ->
                when (resource) {
                    is LoadingResource -> {
                        // TODO show a loading indicator
                    }
                    is SuccessResource -> {
                        // We have a name for a given face id.
                        val faceId = resource.data.first
                        val name = resource.data.second
                        (mGraphicOverlay.find(faceId) as? FaceGraphic)?.setName(name)
                    }
                    is ErrorResource -> {
                        // Just print errors to stdout for now.
                        resource.errorData?.printStackTrace()
                    }
                }
            })
    }