* any values at all. Because of this optimization, {@code build.getValueStrength()} must be
   * {@link Strength#STRONG}.
   *
   * <p>This method is intended to only be used by the internal implementation of {@link Interners},
   * since a map of dummy values is the exact use case there.
   */
  static <K>
      MapMakerInternalMap<K, Dummy, ? extends InternalEntry<K, Dummy, ?>, ?> createWithDummyValues(
          MapMaker builder) {