cdm/src/main/java/thredds/inventory/partition/DirectoryBuilder.java
public List<MFile> readFilesFromIndex(IndexReader indexReader) throws IOException {
    List<MFile> result = new ArrayList<>(100);
    if (index == null) return result;

    indexReader.readMFiles(index, result);
    return result;
  }
public List<MFile> readFilesFromIndex(IndexReader indexReader) throws IOException {
    List<MFile> result = new ArrayList<>(100);
    if (index == null) return result;

    indexReader.readMFiles(index, result);
    return result;
  }
read the list of files from the index