docs: public void removeNode(Node node) {
          Set<TaskTrackerNode> taskTrackerNodes = NODE_MAP.get(node.getGroup());
          if (taskTrackerNodes != null && taskTrackerNodes.size() != 0) {
              TaskTrackerNode taskTrackerNode = new TaskTrackerNode(node.getIdentity());
              taskTrackerNode.setNodeGroup(node.getGroup());
              LOGGER.info("Remove TaskTracker node:{}", taskTrackerNode);
              taskTrackerNodes.remove(taskTrackerNode);
          }
      }