*/
  @ForOverride
  protected abstract boolean doEquivalent(T a, T b);

  /**
   * Returns a hash code for {@code t}.
   *
   * <p>The {@code hash} has the following properties:
   *
   * <ul>
   *   <li>It is <i>consistent</i>: for any reference {@code x}, multiple invocations of {@code
   *       hash(x}} consistently return the same value provided {@code x} remains unchanged