private List<Offset> getIndexSegmentStartOffsetsForLogSegments(List<LogSegmentName> logSegmentNames) {
    List<Offset> offsets = new ArrayList<>();
    for (LogSegmentName logSegmentName : logSegmentNames) {
      File[] indexSegmentFiles = PersistentIndex.getIndexSegmentFilesForLogSegment(tempDirStr, logSegmentName);
      for (File indexSegmentFile : indexSegmentFiles) {
        offsets.add(IndexSegment.getIndexSegmentStartOffset(indexSegmentFile.getName()));
      }
    }
    return offsets;
  }
Gets all the index segment start offsets for the given {@code logSegmentNames}.
@param logSegmentNames the names of the log segments whose index segment start offsets are required.
@return the index segment start offsets for the given {@code logSegmentNames}.
ambry-store/src/test/java/com/github/ambry/store/BlobStoreCompactorTest.java