mutableStateFlow
fun <T> DataStore<Preferences>.mutableStateFlow(key: DataStoreKey<T, *>, scope: CoroutineScope, debounceWrites: Duration = Duration.ZERO): MutableStateFlow<DataStoreValue<T>>
Returns a MutableStateFlow that starts as DataStoreValue.Uninitialized, reflects the latest value of key as DataStoreValue.Loaded emissions, and persists any DataStoreValue.Loaded values set on it (a loaded null value removes the entry; setting DataStoreValue.Uninitialized is a no-op on the store).