code: public static String toStringLimited(ImmutableSet<?> items, int limit) {
      if (items.size() <= limit) {
        return items.toString();
      } else {
        return items.asList().subList(0, limit).toString() + "... (" + (items.size() - limit) + " more)";
      }
    }
docs: Acts like {@code items.toString()} unless {@code items} has more elements than {@code limit},
  in which case it simply prints the number of excess items. This is useful for making toStrings
  for objects which may contain large collections.