return toStringHelper(this)
          .add("aString", aString)
          .add("anInt", anInt)
          .add("anEnum", anEnum)
          .toString();
    }
  }

  /** Validates that the Comparator equivalent we document is correct. */
  @J2ktIncompatible // TODO b/315311435 - J2kt cannot emulate Comparator<C>.<U>thenComparing()
  public void testComparatorEquivalent() {