code: private void handleDeadNode(String nodeName, Set<String> sessions) {
      LOG.info("Notify sessions: " + sessions + " about dead node " + nodeName);
      for (String session : sessions) {
        sessionNotifier.notifyDeadNode(session, nodeName);
      }
    }
docs: All the sessions that had grants on this node should get notified
  @param nodeName the name of the node that went dead