write method
Writes value associated with key to storage.
Implementation
@override
FutureOr<void> write(String key, dynamic value) async {
final encoded = jsonEncode(value);
// Duck-typing support for flutter_secure_storage write.
// ignore: avoid_dynamic_calls
await _secureStorage.write(key: _prefixedKey(key), value: encoded);
_cache[key] = value;
}