code: public static ResourceRecordSet<MXData> mx(String name, Collection<String> mxdata) {
      return new MXBuilder().name(name).addAll(mxdata).build();
    }
docs: creates mx set of {@link denominator.model.rdata.MXData MX} records for the specified name and
  ttl.
  
  @param name   ex. {@code denominator.io.}
  @param mxdata mxdata values ex. {@code [1 mx1.denominator.io., 2 mx2.denominator.io.]}