code: public GroupName getGroupName(@NonNull Map<String, MetricValue> extraTags) {
          return getGroupName(EMPTY_LIST, extraTags);
      }
docs: Create a GroupName from this NamedResolverMap.
  
  @param extraTags Additional tags to put in the tag set. The extraTags
  argument will override any values present in the NamedResolverMap.
  @return A group name derived from this NamedResolverMap and the supplied
  arguments.