default Collection<SingleLogoutUrl> determineLogoutUrl(final RegisteredService registeredService,
                                                           final WebApplicationService singleLogoutService,
                                                           final Optional<HttpServletRequest> httpRequest) {
        return new ArrayList<>();
    }
Determine logout url.

@param registeredService   the registered service
@param singleLogoutService the single logout service
@param httpRequest         the http request
@return the URL
api/cas-server-core-api-logout/src/main/java/org/apereo/cas/logout/slo/SingleLogoutServiceLogoutUrlBuilder.java