docs: public Optional<Authentication> isCasAuthenticationAvailable(final WebContext context) {
          val j2EContext = (J2EContext) context;
          if (j2EContext != null) {
              val tgtId = ticketGrantingTicketCookieGenerator.retrieveCookieValue(j2EContext.getRequest());
  
              if (StringUtils.isNotBlank(tgtId)) {
                  val authentication = ticketRegistrySupport.getAuthenticationFrom(tgtId);
                  if (authentication != null) {
                      return Optional.of(authentication);
                  }
              }
          }
          return Optional.empty();
      }