docs: static String toStringImpl(final Collection<?> collection) {
      StringBuilder sb = newStringBuilderForCollection(collection.size()).append('[');
      STANDARD_JOINER.appendTo(
          sb,
          Iterables.transform(
              collection,
              new Function<Object, Object>() {
                @Override
                public Object apply(Object input) {
                  return input == collection ? "(this Collection)" : input;
                }
              }));
      return sb.append(']').toString();
    }