int k, Comparator<? super T> comparator) {
    checkNonnegative(k, "k");
    checkNotNull(comparator);
    return Collector.of(
        () -> TopKSelector.<T>least(k, comparator),
        TopKSelector::offer,
        TopKSelector::combine,
        TopKSelector::topK,
        Collector.Characteristics.UNORDERED);
  }

  /**

      int k, Comparator<? super T> comparator) {
    checkNonnegative(k, "k");
    checkNotNull(comparator);
    return Collector.of(
        () -> TopKSelector.<T>least(k, comparator),
        TopKSelector::offer,
        TopKSelector::combine,
        TopKSelector::topK,
        Collector.Characteristics.UNORDERED);
  }

  /**

      sort(list, this);
      if (list.size() > k) {
        list.subList(k, list.size()).clear();
      }
      list.trimToSize();
      return unmodifiableList(list);
    } else {
      TopKSelector<E> selector = TopKSelector.least(k, this);
      selector.offerAll(iterator);
      return selector.topK();
    }
  }

  /**

      sort(list, this);
      if (list.size() > k) {
        list.subList(k, list.size()).clear();
      }
      list.trimToSize();
      return unmodifiableList(list);
    } else {
      TopKSelector<E> selector = TopKSelector.least(k, this);
      selector.offerAll(iterator);
      return selector.topK();
    }
  }

  /**