public List<Integer> getIndexes() {
      return indexes;
    }
This class is used to aggregate PlanNode of the same datanode into one rpc. In order to ensure
the one-to-one correspondence between response and request, the corresponding index needs to be
recorded.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/scheduler/AsyncPlanNodeSender.java