code: public static SessionManagerConfig getServerSessionManagerConfig() {
          SessionMgrComponentImpl service = INSTANCE.get().get();
          if (service == null) {
              // no session manager service is available
              return null; 
          }
          return service.getServerConfig();
      }
docs: <p>WXS calls this method, so the signature CANNOT be changed until we define an SPI that WXS can consume.</p>
  <p>We should consider hiding SessionManagerConfig from WXS completely, and provide a new interface with the exact information WXS requires.</p>
  
  @return the configuration of the currently active SessionManager instance