public static void clean() {
    cleanTsFileDir();
    cleanSnapshotDir();
  }
Delete the data directory and all of its subdirectories that contain the
PipeConfig.PIPE_TSFILE_DIR_NAME directory.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/pipe/resource/PipeDataNodeHardlinkOrCopiedFileDirStartupCleaner.java