code: private static List<Contig> getContigsInReadGroupSet(String readGroupSetId,
        SexChromosomeFilter sexChromosomeFilter, OfflineAuth auth) throws IOException {
      List<Contig> contigs = Lists.newArrayList();
      for (CoverageBucket bucket : GenomicsUtils.getCoverageBuckets(readGroupSetId, auth)) {
        if (sexChromosomeFilter == SexChromosomeFilter.EXCLUDE_XY
            && SEX_CHROMOSOME_REGEXP.matcher(bucket.getRange().getReferenceName()).matches()) {
          // X and Y can skew some analysis results
          continue;
        }
        contigs.add(new Contig(bucket.getRange().getReferenceName(),
            (null == bucket.getRange().getStart()) ? 0 : bucket.getRange().getStart(),
                bucket.getRange().getEnd()));
      }
      return contigs;
    }
docs: Retrieve the list of all the reference names and their start=0/end positions for the ranges of
  the coverage buckets computed for this readGroupSet.
  
  @param readGroupSetId - The id of the readGroupSet to query.
  @param sexChromosomeFilter - An enum value indicating how sex chromosomes should be
  handled in the result.
  @return The list of all references in the readGroupSet.
  @throws IOException