setSnowplowUserId method
Implementation
Future<void> setSnowplowUserId(String userId) async {
final timestamp = DateFormat("yyyy-MM-ddTHH:mm:ss").format(DateTime.now());
_cache[_userIdKey] = userId;
_cache[_timestampKey] = timestamp;
await SecureStorage.storeSecureData(_userIdKey, userId);
await SecureStorage.storeSecureData(_timestampKey, timestamp);
}