@Override
    protected String formatOutputMessageInternal(final String message) {
        return this.logoutRequestParameter + '=' + super.formatOutputMessageInternal(message);
    }
A logout http message that is accompanied by a special content type
and formatting.

@author Misagh Moayyed
@since 4.1.0
core/cas-server-core-logout-api/src/main/java/org/apereo/cas/logout/LogoutHttpMessage.java