docs: @GwtIncompatible // NavigableMap
    private static <K, V> NavigableMap<K, V> filterFiltered(
        FilteredEntryNavigableMap<K, V> map, Predicate<? super Entry<K, V>> entryPredicate) {
      Predicate<Entry<K, V>> predicate =
          Predicates.<Entry<K, V>>and(map.entryPredicate, entryPredicate);
      return new FilteredEntryNavigableMap<K, V>(map.unfiltered, predicate);
    }