code: @Override
      public int getInUseSessionVersion(ServletRequest req, SessionAffinityContext sac) {
          int version = sac.getResponseSessionVersion();
          if (version == -1) { // not set, use request version
              version = sac.getRequestedSessionVersion();
          }
          return version;
      }
docs: /*
  Method to get the appropriate version to use for a new session. May be the
  response session id
  if the request has been dispatched adn the response version is already set