private Map<LogSegmentName, SortedMap<Offset, File>> getLogSegmentsToIndexSegmentsMap(
      List<LogSegmentName> logSegmentNames) {
    Map<LogSegmentName, SortedMap<Offset, File>> logSegmentsToIndexSegmentDetails = new HashMap<>();
    for (LogSegmentName logSegmentName : logSegmentNames) {
      logSegmentsToIndexSegmentDetails.put(logSegmentName, getIndexSegmentDetails(logSegmentName));
    }
    return logSegmentsToIndexSegmentDetails;
  }
Gets a map of all the index segment files that cover the given {@code logSegmentNames}.
@param logSegmentNames the names of log segments whose index segment files are required.
@return a map keyed on log segment name and containing details about all the index segment files that refer to it.
ambry-store/src/main/java/com/github/ambry/store/BlobStoreCompactor.java