return asMapEntryIterator(set, function);
    }

    @Override
    @GwtIncompatible("Spliterator")
    Spliterator<Entry<K, V>> entrySpliterator() {
      return CollectSpliterators.map(
          set.spliterator(),
          Spliterator.DISTINCT | Spliterator.NONNULL,
          e -> immutableEntry(e, function.apply(e)));
    }

    @Override