return comparator.compare(a, b);
  }

  @Override
  public boolean equals(@CheckForNull Object object) {
    if (object == this) {
      return true;
    }
    if (object instanceof ComparatorOrdering) {
      ComparatorOrdering<?> that = (ComparatorOrdering<?>) object;
      return this.comparator.equals(that.comparator);
    }
    return false;
  }

  @Override
  public int hashCode() {

    @Override
    public String toString() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.toString();
    }

    @Override
    public boolean equals(@Nullable Object o) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.equals(o);
    }

    @Override
    public int hashCode() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.hashCode();
    }

    @Override

   * required, to have the following properties:
   *
   * <ul>
   *   <li>Its execution does not cause any observable side effects.
   *   <li>The computation is <i>consistent with equals</i>; that is, {@link Objects#equal
   *       Objects.equal}{@code (a, b)} implies that {@code predicate.apply(a) ==
   *       predicate.apply(b))}.
   * </ul>
   *

  public static Equivalence<Object> identity() {
    return Identity.INSTANCE;
  }

  static final class Equals extends Equivalence<Object> implements Serializable {

    static final Equals INSTANCE = new Equals();

    @Override
    protected boolean doEquivalent(Object a, Object b) {
      return a.equals(b);
    }

    @Override
    protected int doHash(Object o) {
      return o.hashCode();
    }

  /** Constructor for use by subclasses. */
  protected ForwardingSet() {}

  @Override
  protected abstract Set<E> delegate();

  @Override
  public boolean equals(@CheckForNull Object object) {
    return object == this || delegate().equals(object);
  }

  @Override
  public int hashCode() {
    return delegate().hashCode();
  }

  /**

  }

  @Override
  public List<E> subList(int fromIndex, int toIndex) {
    return delegate().subList(fromIndex, toIndex);
  }

  @Override
  public boolean equals(@CheckForNull Object object) {
    return object == this || delegate().equals(object);
  }

  @Override
  public int hashCode() {
    return delegate().hashCode();
  }

  /**

    }
    return hash;
  }

  @Override
  public boolean equals(@CheckForNull Object object) {
    if (object instanceof PairwiseEquivalence) {
      @SuppressWarnings("unchecked")
      PairwiseEquivalence<Object, Object> that = (PairwiseEquivalence<Object, Object>) object;
      return this.elementEquivalence.equals(that.elementEquivalence);
    }

    return false;
  }

  @Override

  public int hashCode() {
    return -forwardOrder.hashCode();
  }

  @Override
  public boolean equals(@CheckForNull Object object) {
    if (object == this) {
      return true;
    }
    if (object instanceof ReverseOrdering) {
      ReverseOrdering<?> that = (ReverseOrdering<?>) object;
      return this.forwardOrder.equals(that.forwardOrder);
    }
    return false;
  }

  @Override

    HashCode hashCodeB = HashCode.fromBytes(bytesB);

    // They aren't equal...
    assertFalse(hashCodeA.equals(hashCodeB));

    // But they still have the same Object#hashCode() value.
    // Technically not a violation of the equals/hashCode contract, but...?
    assertEquals(hashCodeA.hashCode(), hashCodeB.hashCode());
  }

  public void testRoundTripHashCodeUsingFromString() {

    // instead of Object[].
    return delegateList().toArray(new Object[size()]);
  }

  @Override
  public boolean equals(@Nullable Object obj) {
    return delegateList().equals(obj);
  }

  @Override
  public int hashCode() {
    return delegateList().hashCode();
  }

  @Override
  public UnmodifiableIterator<E> iterator() {