@Override
    public void onFinish(ISink sink) {
      if (LOGGER.isDebugEnabled()) {
        LOGGER.debug("[SkHListenerOnFinish]");
      }
      decrementCnt();
    }
Listen to the state changes of a sink handle.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/exchange/MPPDataExchangeManager.java