@Override
    public void setDriverTaskId(DriverTaskId driverTaskId) {
      stubDriver = driverTaskId;
    }
a comparator of DriverTask, the higher the levelScheduledTime is, the lower order it has.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/schedule/task/DriverTask.java