code: public List<VariantContext> query(Region region) throws Exception {
          return query(region, null, new VariantOptions(), VariantContext.class);
      }
docs: This method aims to provide a very simple, safe and quick way of accessing to a small fragment of the VCF file.
  This must not be used in production for reading big data files. It returns a maximum of 10,000 variant records.
  
  @param region @return
  @throws IOException