PasscodeScreen(
  title: title,
  passwordEnteredCallback: _onPasscodeEntered,
  cancelLocalizedText: 'Cancel',
  deleteLocalizedText: 'Delete',
  shouldTriggerVerification: _verificationNotifier.stream,  
);

_onPasscodeEntered(String enteredPasscode) {
  
}

final StreamController<bool> _verificationNotifier = StreamController<bool>.broadcast();

_onPasscodeEntered(String enteredPasscode) {
  bool isValid = '123456' == enteredPassword;
  _verificationNotifier.add(isValid);
}

@override
void dispose() {
  _verificationNotifier.close();
  super.dispose();
}

class CircleUIConfig {
  final Color borderColor;
  final Color fillColor;
  final double borderWidth;
  final double circleSize;
  double extraSize;
}

class KeyboardUIConfig {
  final double digitSize;
  final TextStyle digitTextStyle;
  final TextStyle deleteButtonTextStyle;
  final Color primaryColor;
  final Color digitFillColor;
  final EdgeInsetsGeometry keyboardRowMargin;
  final EdgeInsetsGeometry deleteButtonMargin;
}