clear static method
Implementation
static Future<void> clear() async {
await Future.wait([
_storage.delete(key: _AUTHENTICATION_TOKEN_KEY),
_storage.delete(key: _ID_TOKEN_KEY),
_storage.delete(key: _REFRESH_TOKEN_KEY),
_storage.delete(key: _TOKEN_TYPE_KEY),
_storage.delete(key: _EXPIRES_ON_KEY),
_storage.delete(key: _STATE_KEY)
]);
}