code: public void ensureFailover( HttpServletRequest request )
      {
          StorageHandler sh = Handlers.get( getServletContext() ).getStorageHandler();
          HttpServletRequest unwrappedRequest = PageFlowUtils.unwrapMultipart( request );
          RequestContext rc = new RequestContext( unwrappedRequest, null );
          String attr =
                  ScopedServletUtils.getScopedSessionAttrName( InternalConstants.FACES_BACKING_ATTR, unwrappedRequest );
          sh.ensureFailover( rc, attr, this );
      }
docs: Ensures that any changes to this object will be replicated in a cluster (for failover),
  even if the replication scheme uses a change-detection algorithm that relies on
  HttpSession.setAttribute to be aware of changes.  Note that this method is used by the framework
  and does not need to be called explicitly in most cases.
  
  @param request the current HttpServletRequest