public String toString() {
      return "ByteSource.empty()";
    }
  }

  private static final class ConcatenatedByteSource extends ByteSource {

    final Iterable<? extends ByteSource> sources;

    ConcatenatedByteSource(Iterable<? extends ByteSource> sources) {
      this.sources = checkNotNull(sources);
    }

    @Override
    public InputStream openStream() throws IOException {

    list.add("a");
    try {
      assertEmpty(list);
      throw new Error();
    } catch (AssertionFailedError expected) {
    }
    try {
      assertEmpty(
          new Iterable<String>() {
            @Override
            public Iterator<String> iterator() {
              return singleton("a").iterator();
            }
          });
      throw new Error();

    list.add("a");
    try {
      assertEmpty(list);
      throw new Error();
    } catch (AssertionFailedError expected) {
    }
    try {
      assertEmpty(
          new Iterable<String>() {
            @Override
            public Iterator<String> iterator() {
              return singleton("a").iterator();
            }
          });
      throw new Error();

    return Sets.union(predecessors(), successors());
  }

  @Override
  public Set<E> incidentEdges() {
    return new AbstractSet<E>() {
      @Override
      public UnmodifiableIterator<E> iterator() {
        Iterable<E> incidentEdges =
            (selfLoopCount == 0)
                ? Iterables.concat(inEdgeMap.keySet(), outEdgeMap.keySet())
                : Sets.union(inEdgeMap.keySet(), outEdgeMap.keySet());

    return new CacheBuilderFactory()
        .withKeyStrengths(ImmutableSet.of(STRONG, Strength.WEAK))
        .withValueStrengths(ImmutableSet.of(STRONG, Strength.WEAK, Strength.SOFT));
  }

  private Iterable<LoadingCache<Key, String>> caches() {
    CacheBuilderFactory factory = factoryWithAllKeyStrengths();
    return Iterables.transform(
        factory.buildAllPermutations(),

        this.repositories = remoteRepositoryManager.aggregateRepositories(session, repositories, newRepositories, true);
    }

    private static void removeMatchingRepository(Iterable<RemoteRepository> repositories, final String id) {
        Iterator<RemoteRepository> iterator = repositories.iterator();
        while (iterator.hasNext()) {
            RemoteRepository remoteRepository = iterator.next();

              public SortedMultiset<E> create(Object... entries) {
                return ((SortedMultiset<E>) super.create(entries)).descendingMultiset();
              }

              @Override
              public Iterable<E> order(List<E> insertionOrder) {
                return ImmutableList.copyOf(super.order(insertionOrder)).reverse();
              }
            })
        .named(parentBuilder.getName() + " descending")

                      map.put(entry.getKey(), entry.getValue());
                    }
                    return map;
                  }

                  @Override
                  public Iterable<Entry<String, String>> order(
                      List<Entry<String, String>> insertionOrder) {
                    sort(
                        insertionOrder,

                      map.put(entry.getKey(), entry.getValue());
                    }
                    return map;
                  }

                  @Override
                  public Iterable<Entry<String, String>> order(
                      List<Entry<String, String>> insertionOrder) {
                    sort(
                        insertionOrder,

  /**
   * Returns a sequential {@link Stream} of the contents of {@code iterable}, delegating to {@link
   * Collection#stream} if possible.
   */
  public static <T extends @Nullable Object> Stream<T> stream(Iterable<T> iterable) {
    return (iterable instanceof Collection)
        ? ((Collection<T>) iterable).stream()
        : StreamSupport.stream(iterable.spliterator(), false);
  }

  /**
   * Returns {@link Collection#stream}.