docs: ArrayTagSet addAll(Iterable<Tag> ts) {
      if (ts instanceof Collection) {
        Collection<Tag> data = (Collection<Tag>) ts;
        if (data.isEmpty()) {
          return this;
        } else {
          Tag[] newTags = new Tag[data.size()];
          int i = 0;
          for (Tag t : data) {
            newTags[i] = BasicTag.convert(t);
            ++i;
          }
          return addAll(newTags);
        }
      } else {
        List<Tag> data = new ArrayList<>();
        for (Tag t : ts) {
          data.add(t);
        }
        return addAll(data);
      }
    }