code: public static Iterable<CallSet> getCallSets(String variantSetId, OfflineAuth auth)
        throws IOException {
      Genomics genomics = GenomicsFactory.builder().build().fromOfflineAuth(auth);
      return Paginator.Callsets.create(genomics)
          .search(new SearchCallSetsRequest().setVariantSetIds(Lists.newArrayList(variantSetId)),
              "callSets,nextPageToken");
    }
docs: Gets CallSets for a given variantSetId using the Genomics API.
  
  @param variantSetId The id of the variantSet to query.
  @param auth The OfflineAuth for the API request.
  @return The list of callSet names in the variantSet.
  @throws IOException If variantSet does not contain any CallSets.