CreateViewModelExtension.kt

    @Suppress("UNCHECKED_CAST")
    private inline fun <reified T : ViewModel> createViewModel(key: String, crossinline initializer: () -> T): T {
        val factory = object : ViewModelProvider.NewInstanceFactory() {
            override fun <T : ViewModel?> create(modelClass: Class<T>): T = initializer() as T
        }
        return ViewModelProviders.of(activity, factory).get(key, T::class.java)
    }