* successful input futures. The list of results is in the same order as the input list, and if
   * any of the provided futures fails or is canceled, its corresponding position will contain
   * {@code null} (which is indistinguishable from the future having a successful value of {@code
   * null}).
   *
   * <p>The list of results is in the same order as the input list.
   *

    MapDifference<Integer, String> same = Maps.difference(left, right);
    MapDifference<Integer, String> reverse = Maps.difference(right, left);
    MapDifference<Integer, String> diff2 = Maps.difference(left, right2);

    new EqualsTester()
        .addEqualityGroup(original, same)
        .addEqualityGroup(reverse)
        .addEqualityGroup(diff2)
        .testEquals();

   *
   * <p>The iteration order of the returned set follows the enum's iteration order, not the order in
   * which the elements appear in the given collection.
   *
   * @param elements the elements, all of the same {@code enum} type, that the set should contain
   * @return an immutable set containing those elements, minus duplicates
   */
  public static <E extends Enum<E>> ImmutableSet<E> immutableEnumSet(Iterable<E> elements) {

 *
 * <h3>Cancelling</h3>
 *
 * Any step in a pipeline can be {@linkplain #cancel(boolean) cancelled}, even after another step
 * has been derived, with the same semantics as cancelling a {@link Future}. In addition, a
 * successfully cancelled step will immediately start closing all objects captured for later closing
 * by it and by its input steps.
 *
 * <h3>Ending a pipeline</h3>

    MapDifference<Integer, String> same = Maps.difference(left, right);
    MapDifference<Integer, String> reverse = Maps.difference(right, left);
    MapDifference<Integer, String> diff2 = Maps.difference(left, right2);

    new EqualsTester()
        .addEqualityGroup(original, same)
        .addEqualityGroup(reverse)
        .addEqualityGroup(diff2)
        .testEquals();

      Comparator<? super K> comparator) {
    return fromEntries(checkNotNull(comparator), false, entries);
  }

  /**
   * Returns an immutable map containing the same entries as the provided sorted map, with the same
   * ordering.
   *
   * <p>Despite the method name, this method attempts to avoid actually copying the data when it is
   * safe to do so. The exact circumstances under which a copy will or will not be performed are

        result = true;
      }
    }
    return result;
  }

  /**
   * Determines whether two iterators contain equal elements in the same order. More specifically,
   * this method returns {@code true} if {@code iterator1} and {@code iterator2} contain the same
   * number of elements and every element of {@code iterator1} is equal to the corresponding element
   * of {@code iterator2}.
   *

    testConcurrentLoading(CacheBuilder.newBuilder().expireAfterWrite(10, SECONDS));
  }

  /**
   * On a successful concurrent computation, only one thread does the work, but all the threads get
   * the same result.
   */
  private static void testConcurrentLoadingDefault(CacheBuilder<Object, Object> builder)
      throws InterruptedException {

    int count = 10;
    AtomicInteger callCount = new AtomicInteger();

    testConcurrentLoading(CacheBuilder.newBuilder().expireAfterWrite(10, SECONDS));
  }

  /**
   * On a successful concurrent computation, only one thread does the work, but all the threads get
   * the same result.
   */
  private static void testConcurrentLoadingDefault(CacheBuilder<Object, Object> builder)
      throws InterruptedException {

    int count = 10;
    AtomicInteger callCount = new AtomicInteger();

   * comparison to determine equality of keys. Its {@link Cache#asMap} view will therefore
   * technically violate the {@link Map} specification (in the same way that {@link IdentityHashMap}
   * does).
   *
   * <p>Entries with keys that have been garbage collected may be counted in {@link Cache#size}, but