class SomeViewModelFactory(
        private val owner: SavedStateRegistryOwner,
        private val defaultArgs: Bundle,
        private val someString: String) : AbstractSavedStateViewModelFactory(owner, defaultArgs) {
    override fun <T : ViewModel?> create(key: String, modelClass: Class<T>, state: SavedStateHandle) =
            SomeViewModel(state, someString) as T
}

class SomeViewModel(private val state: SavedStateHandle, private val someString: String) : ViewModel() {
    // The default value is used from 'defaultArgs' since 'defaultArgs' are saved in the ViewModelFactory.
    val someInt = state.get<Int>(SOME_INT_KEY)
        
    init {
        //TODO: Use 'defaultString' and 'someString' to init process when VM is created. i.e. Get data request.
    }
        
     fun saveSomeInt(someInt: Int) {
        state.set(SOME_INT_KEY, position)
    }
}

class Fragment: Fragment() {
    // Create VM in activity/fragment with VM factory.
    // Don't forget to add "kotlinOptions { jvmTarget = '1.8' }" to "android" build.gradle (:app)
    val someViewModel: SomeViewModel by viewModels { SomeViewModelFactory(
            savedStateRegistryOwner = this, 
            defaultArgs = Bundle().apply {
               putInt(SOME_INT_KEY, 18)
            },
            someString = "someString") } 
    private var someInt: Int = 0
     
    override fun onSaveInstanceState(outState: Bundle) {
        super.onSaveInstanceState(outState)
        someViewModel.saveSomeInt(...)
    }    
        
    override fun onViewStateRestored(savedInstanceState: Bundle?) {
        super.onViewStateRestored(savedInstanceState)
        someInt = someViewModel.someInt
    }
}