* invoke methods, they invoke methods on the {@code ForwardingNavigableSet}.
 *
 * <p>Each of the {@code standard} methods uses the set's comparator (or the natural ordering of the
 * elements, if there is no comparator) to test element equality. As a result, if the comparator is
 * not consistent with equals, some of the standard implementations may violate the {@code Set}
 * contract.
 *

    return new ForwardingSet<E>() {
      @Override
      protected Set<E> delegate() {
        return set;
      }

      @Override
      public boolean add(@ParametricNullness E element) {
        throw new UnsupportedOperationException();
      }

      @Override
      public boolean addAll(Collection<? extends E> es) {
        throw new UnsupportedOperationException();
      }

    return new ForwardingSet<E>() {
      @Override
      protected Set<E> delegate() {
        return set;
      }

      @Override
      public boolean add(@ParametricNullness E element) {
        throw new UnsupportedOperationException();
      }

      @Override
      public boolean addAll(Collection<? extends E> es) {
        throw new UnsupportedOperationException();
      }

    addEdge(N1, N1, E11);
    assertThat(network.outDegree(N1)).isEqualTo(1);
    addEdge(N1, N2, E12);
    assertThat(network.outDegree(N1)).isEqualTo(2);
  }

  // Element Mutation

  @Test
  public void addEdge_existingNodes() {
    assume().that(graphIsMutable()).isTrue();

    // Adding nodes initially for safety (insulating from possible future

    addEdge(N1, N1, E11);
    assertThat(network.outDegree(N1)).isEqualTo(1);
    addEdge(N1, N2, E12);
    assertThat(network.outDegree(N1)).isEqualTo(2);
  }

  // Element Mutation

  @Test
  public void addEdge_existingNodes() {
    assume().that(graphIsMutable()).isTrue();

    // Adding nodes initially for safety (insulating from possible future

// Get an aggregated storage info across all disks.
func getStorageInfo(disks []StorageAPI, endpoints []Endpoint, metrics bool) StorageInfo {
	disksInfo := getDisksInfo(disks, endpoints, metrics)

	// Sort so that the first element is the smallest.
	sort.Slice(disksInfo, func(i, j int) bool {
		return disksInfo[i].TotalSpace < disksInfo[j].TotalSpace
	})

	storageInfo := StorageInfo{
		Disks: disksInfo,
	}

}

//msgp:ignore dataUsageEntryInfo
type dataUsageEntryInfo struct {
	Name   string
	Parent string
	Entry  dataUsageEntry
}

type dataUsageCacheInfo struct {
	// Name of the bucket. Also root element.
	Name       string
	NextCycle  uint32
	LastUpdate time.Time
	// indicates if the disk is being healed and scanner
	// should skip healing the disk
	SkipHealing bool

	i := len(dirPath)
	for i > 0 && os.IsPathSeparator(dirPath[i-1]) { // Skip trailing path separator.
		i--
	}

	j := i
	for j > 0 && !os.IsPathSeparator(dirPath[j-1]) { // Scan backward over element.
		j--
	}

	if j > 1 {
		// Create parent.
		if err := osMkdirAll(dirPath[:j-1], perm, baseDir); err != nil {
			return err
		}
	}

	// Parent now exists; invoke Mkdir and use its result.

        C filtered = filter(unfiltered, EVEN);
        List<Integer> foundElements = new ArrayList<>();
        filtered.forEach(
            (Integer i) -> {
              assertTrue("Unexpected element: " + i, EVEN.apply(i));
              foundElements.add(i);
            });
        assertEquals(ImmutableList.copyOf(filtered), foundElements);
      }
    }
  }

                  protected Set<String> create(String[] elements) {
                    return ImmutableMultiset.copyOf(elements).elementSet();
                  }
                })
            .named("ImmutableMultiset, element set")
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.SERIALIZABLE,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .createTestSuite());