code: public void setPriority(SessionPriority prio) throws IOException {
      if (failException != null) {
        throw failException;
      }
  
      sessionInfo.priority = prio;
  
      SessionInfo newInfo = new SessionInfo(sessionInfo);
      cmNotifier.addCall(
          new ClusterManagerService.sessionUpdateInfo_args(sessionId, newInfo));
    }
docs: Set the priority for this session in the ClusterManager
  @param prio the priority of this session
  @throws IOException