private String handleProxyIouDelivery(final Credential serviceCredential, final Ticket proxyGrantingTicket) throws Throwable {
        return serviceValidateConfigurationContext.getProxyHandler().handle(serviceCredential, proxyGrantingTicket);
    }
Enforce ticket validation authorization for.

@param request   the request
@param service   the service
@param assertion the assertion
support/cas-server-support-validation-core/src/main/java/org/apereo/cas/web/AbstractServiceValidateController.java