openSSSS method 
    
    
    
  Implementation
  Future<void> openSSSS({
  String? passphrase,
  String? recoveryKey,
  String? keyOrPassphrase,
  bool skip = false,
}) async {
  Future<void> next() async {
    if (_nextAction == 'request') {
      await sendRequest();
    } else if (_nextAction == 'done') {
      // and now let's sign them all in the background
      unawaited(encryption.crossSigning.sign(_verifiedDevices));
      setState(KeyVerificationState.done);
    } else if (_nextAction == 'showQRSuccess') {
      setState(KeyVerificationState.showQRSuccess);
    }
  }
  if (skip) {
    await next();
    return;
  }
  final handle = encryption.ssss.open(EventTypes.CrossSigningUserSigning);
  await handle.unlock(
    passphrase: passphrase,
    recoveryKey: recoveryKey,
    keyOrPassphrase: keyOrPassphrase,
  );
  await handle.maybeCacheAll();
  await next();
}