@Override
  protected AsyncRequestRPCHandler<?, CnToDnAsyncRequestType, TDataNodeLocation> buildHandler(
      AsyncRequestContext<?, ?, CnToDnAsyncRequestType, TDataNodeLocation> requestContext,
      int requestId,
      TDataNodeLocation targetNode) {
    return DataNodeAsyncRequestRPCHandler.buildHandler(requestContext, requestId, targetNode);
  }
Asynchronously send RPC requests to DataNodes. See queryengine.thrift for more details.
iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/client/async/CnToDnInternalServiceAsyncRequestManager.java