This package allows you to save key-value and use native backup system.
Android documentation: https://developer.android.com/guide/topics/data/keyvaluebackup#:~:text=Android%20Backup%20Service%20provides%20cloud,to%20the%20device's%20backup%20transport.
IOS documentation: https://developer.apple.com/documentation/foundation/nsubiquitouskeyvaluestore
Future<String?> get({required String key});
Future<void> save({required String key, required String? value});
Future<void> delete({required String key});
Future<void> deleteAll();