HashSet<String> mut =
        Sets.symmetricDifference(friends, enemies).copyInto(new HashSet<String>());

    enemies.add("Dave");
    assertEquals(3, symmetricDifferenceFriendsFirst.size());
    assertEquals(4, immut.size());
    assertEquals(4, mut.size());

    immut = Sets.symmetricDifference(enemies, friends).immutableCopy();

    HashSet<String> mut =
        Sets.symmetricDifference(friends, enemies).copyInto(new HashSet<String>());

    enemies.add("Dave");
    assertEquals(3, symmetricDifferenceFriendsFirst.size());
    assertEquals(4, immut.size());
    assertEquals(4, mut.size());

    immut = Sets.symmetricDifference(enemies, friends).immutableCopy();

                  : new MutatedOnQueryList<>(
                      transform(infiniteSetsFromStartIndex, ImmutableList::copyOf));
          Set<String> immutableCopy;
          try {
            immutableCopy = copyOf(input);
          } catch (RuntimeException e) {
            throw new RuntimeException(
                Strings.lenientFormat(