docs: private Set<K> determineExcludedKeys(IntFunction<Set<K>> keysToExclude, IntSet segmentsToUse) {
        if (keysToExclude == null) {
           return Collections.emptySet();
        }
  
        // Special map only supports get operations
        return segmentsToUse.intStream().mapToObj(s -> {
           Set<K> keysForSegment = keysToExclude.apply(s);
           if (keysForSegment != null) {
              return keysForSegment.stream();
           }
           return null;
        }).flatMap(Function.identity()).collect(Collectors.toSet());
     }