protected void createDuoRedirectToRegistrationAction(final List<AbstractStateModel> states) {
        val endModel = new ViewStateModel(VIEW_ID_REDIRECT_TO_DUO_REGISTRATION);
        endModel.setView("externalRedirect:#{flowScope.duoRegistrationUrl}?");
        states.add(endModel);
    }
This is {@link DuoSecurityMultifactorWebflowConfigurer}.

@author Misagh Moayyed
@since 5.0.0
support/cas-server-support-duo-core/src/main/java/org/apereo/cas/adaptors/duo/web/flow/DuoSecurityMultifactorWebflowConfigurer.java