@Override
  public void transfer(final Event event) throws Exception {
    // in order to commit in order
    if (isTabletBatchModeEnabled && !tabletBatchBuilder.isEmpty()) {
      doTransfer();
    }

    // Only deletion event will be passed here.
    doTransferWrapper((PipeDeleteDataNodeEvent) event);
  }
This connector is used for PipeConsensus to transfer queued event.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/pipe/connector/protocol/pipeconsensus/PipeConsensusSyncConnector.java