private void createConnection(final SyncIdentityInfo identityInfo) {
    final long connectionId = connectionIdGenerator.incrementAndGet();
    currentConnectionId.set(connectionId);
    connectionIdToIdentityInfoMap.put(connectionId, identityInfo);
  }
Create connection from sender.

@return {@link TSStatusCode#PIPESERVER_ERROR} if fail to connect; {@link
    TSStatusCode#SUCCESS_STATUS} if success to connect.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/pipe/receiver/protocol/legacy/IoTDBLegacyPipeReceiverAgent.java