* all elements that are contained by {@code set1} and not contained by {@code set2}. {@code set2}
   * may also contain elements not present in {@code set1}; these are simply ignored. The iteration
   * order of the returned set matches that of {@code set1}.
   *
   * <p>Results are undefined if {@code set1} and {@code set2} are sets based on different

func (s *erasureSets) LocalStorageInfo(ctx context.Context, metrics bool) StorageInfo {
	var storageInfo StorageInfo

	storageInfos := make([]StorageInfo, len(s.sets))

	g := errgroup.WithNErrs(len(s.sets))
	for index := range s.sets {
		index := index
		g.Go(func() error {
			storageInfos[index] = s.sets[index].LocalStorageInfo(ctx, metrics)
			return nil

// consistently for a given object name.
func TestHashedLayer(t *testing.T) {
	// Test distribution with 16 sets.
	var objs [16]*erasureObjects
	for i := range objs {
		objs[i] = &erasureObjects{}
	}

	sets := &erasureSets{sets: objs[:], distributionAlgo: "CRCMOD"}

	testCases := []struct {
		objectName  string
		expectedObj *erasureObjects
	}{

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

	}
	if len(formatV3.Erasure.Sets) != 1 {
		t.Fatalf("expected single set after migrating from v1 to v3, but found %d", len(formatV3.Erasure.Sets))
	}
	if !reflect.DeepEqual(formatV3.Erasure.Sets[0], m.Erasure.JBOD) {
		t.Fatalf("expected drive uuid: %v, got: %v", m.Erasure.JBOD, formatV3.Erasure.Sets[0])
	}

	m = &formatErasureV1{}
	m.Format = "unknown"

    Set<Feature<?>> features = Sets.<Feature<?>>newHashSet(ExampleBaseFeature.BASE_FEATURE_1);
    assertSame(features, FeatureUtil.addImpliedFeatures(features));
  }

  public void testAddImpliedFeatures_addsImpliedFeatures() throws Exception {
    Set<Feature<?>> features;

    features = Sets.<Feature<?>>newHashSet(ExampleDerivedFeature.DERIVED_FEATURE_1);

  private Iterable<List<Object>> buildCartesianProduct(Set<?>... sets) {
    List<Set<Optional<?>>> optionalSets = Lists.newArrayListWithExpectedSize(sets.length);
    for (Set<?> set : sets) {
      Set<Optional<?>> optionalSet =
          Sets.newLinkedHashSet(Iterables.transform(set, NULLABLE_TO_OPTIONAL));
      optionalSets.add(optionalSet);
    }
    Set<List<Optional<?>>> cartesianProduct = Sets.cartesianProduct(optionalSets);

    resetContainer(
        Helpers.mapEntry(k0(), v0()), Helpers.mapEntry(k1(), v0()), Helpers.mapEntry(k0(), v3()));
    Set<Entry<K, Collection<V>>> expected = Sets.newHashSet();
    expected.add(Helpers.mapEntry(k0(), (Collection<V>) Sets.newHashSet(v0(), v3())));
    expected.add(Helpers.mapEntry(k1(), (Collection<V>) Sets.newHashSet(v0())));
    new EqualsTester().addEqualityGroup(expected, multimap().asMap().entrySet()).testEquals();
  }

     */
    PluginVersionRequest setRepositories(List<RemoteRepository> repositories);

    /**
     * Gets the session to use for repository access.
     *
     * @return The repository session or {@code null} if not set.
     */
    RepositorySystemSession getRepositorySession();

    /**
     * Sets the session to use for repository access.
     *
     * @param repositorySession The repository session to use.

                  @Override
                  protected Set<String> create(String[] elements) {
                    Set<String> set = Sets.newHashSet("b", "c");
                    Set<String> other = Sets.newHashSet("a", "b", "c", "d");
                    return Sets.difference(set, other);
                  }
                })
            .named("set - superset")
            .withFeatures(