private static String getFileDataDir(final SyncIdentityInfo identityInfo) {
    return getReceiverPipeDir(
            identityInfo.getPipeName(),
            identityInfo.getRemoteAddress(),
            identityInfo.getCreateTime())
        + File.separator
        + FILE_DATA_DIR_NAME;
  }
Get current FileStartIndex.

@return startIndex of file: -1 if file doesn't exist
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/pipe/receiver/protocol/legacy/IoTDBLegacyPipeReceiverAgent.java