* {@link TreeSet} or the {@link Map#keySet} of an {@code IdentityHashMap}.
   */
  public static <E extends @Nullable Object> SetView<E> union(
      final Set<? extends E> set1, final Set<? extends E> set2) {
    checkNotNull(set1, "set1");
    checkNotNull(set2, "set2");

    return new SetView<E>() {
      @Override
      public int size() {
        int size = set1.size();

	set1 := newStatefulSet(3)
	set2 := newStatefulSet(3)
	set2.Name = "foo2"
	set3 := newStatefulSet(3)
	set3.Name = "foo3"
	set3.Spec.Selector.MatchLabels = map[string]string{"foo3": "bar"}
	pod := newStatefulSetPod(set1, 0)
	om.setsIndexer.Add(set1)
	om.setsIndexer.Add(set2)
	om.setsIndexer.Add(set3)

	// Make pod an orphan. Expect matching sets to be queued.
	pod.OwnerReferences = nil

    def "provides stores"() {
        def set1 = f.createStoreSet()
        def set2 = f.createStoreSet()

        expect:
        set1.oldModelCache().load(() -> "1") == "1"
        set1.oldModelCache().load(() -> "2") == "1"
        set2.oldModelCache().load(() -> "3") == "3"

        set1.newModelCache().load(() -> "1") == "1"
        set1.newModelCache().load(() -> "2") == "1"
        set2.newModelCache().load(() -> "3") == "3"
    }

                  @Override
                  protected Set<String> create(String[] elements) {
                    Set<String> set1 = Sets.newHashSet(elements);
                    set1.add(samples().e3());
                    Set<String> set2 = Sets.newHashSet(elements);
                    set2.add(samples().e4());
                    return Sets.intersection(set1, set2);
                  }
                })

                  @Override
                  protected Set<String> create(String[] elements) {
                    Set<String> set1 = Sets.newHashSet(elements);
                    set1.add(samples().e3());
                    Set<String> set2 = Sets.newHashSet(elements);
                    set2.add(samples().e4());
                    return Sets.intersection(set1, set2);
                  }
                })

	for {
		select {
		case <-ctx.Done():
			return
		case <-timer.C:
			var wg sync.WaitGroup
			for _, set := range s.sets {
				wg.Add(1)
				go func(set *erasureObjects) {
					defer wg.Done()
					if set == nil {
						return
					}
					set.cleanupDeletedObjects(ctx)
				}(set)
			}
			wg.Wait()

			// Reset for the next interval
			timer.Reset(globalAPIConfig.getDeleteCleanupInterval())

	return ret
}

// Insert adds items to the set.
func (s Set[T]) Insert(items ...T) Set[T] {
	for _, item := range items {
		s[item] = Empty{}
	}
	return s
}

func Insert[T comparable](set Set[T], items ...T) Set[T] {
	return set.Insert(items...)
}

// Delete removes all items from the set.
func (s Set[T]) Delete(items ...T) Set[T] {
	for _, item := range items {
		delete(s, item)
	}
	return s
}

		items2 = append(items2, fmt.Sprint(i))
	}
	b.Run("Set", func(b *testing.B) {
		set1000 := sets.New(items1000...)
		set100 := sets.New(items100...)
		set2 := sets.New(items2...)
		b.Run("New/1", func(b *testing.B) {
			for range b.N {
				_ = sets.New("a")
			}
		})
		b.Run("New/1000", func(b *testing.B) {
			for range b.N {
				_ = sets.New(items1000...)
			}
		})

	// Retention configuration, needed to be passed along with lifecycle if set.
	Retention lock.Retention `msg:"-"`

	// Replication configuration
	Replication replicationConfig `msg:"-"`

	// StopDiskAtLimit will stop listing on each disk when limit number off objects has been returned.
	StopDiskAtLimit bool

	// pool and set of where the cache is located.
	pool, set int
}

func init() {
	gob.Register(listPathOptions{})

    SortedSet<String> set = of("a", "b", "c");
    assertEquals(set, Sets.newTreeSet(asList("a", "b", "c")));
    assertEquals(Sets.newTreeSet(asList("a", "b", "c")), set);
    assertFalse(set.equals(Sets.newTreeSet(asList("a", "b", "d"))));
    assertFalse(Sets.newTreeSet(asList("a", "b", "d")).equals(set));
    assertFalse(set.equals(Sets.newHashSet(4, 5, 6)));
    assertFalse(Sets.newHashSet(4, 5, 6).equals(set));
  }