docs: private void initMainStemStatus() {
          String path = null;
          try {
              path = StagePathUtils.getMainStem(getPipelineId());
              byte[] bytes = zookeeper.readData(path);
              initMainStemStatus(bytes);
          } catch (ZkNoNodeException e) {
              // mainstem节点挂了后，状态直接修改为taking
              mainStemStatus = MainStemEventData.Status.TAKEING;
              permitSem();
          } catch (ZkException e) {
              logger.error(path, e);
          }
      }