code: <K extends T, V> Map<K, V> createMap(int expectedSize) {
      switch (type) {
        case UNORDERED:
          return Maps.newHashMapWithExpectedSize(expectedSize);
        case INSERTION:
          return Maps.newLinkedHashMapWithExpectedSize(expectedSize);
        case SORTED:
          return Maps.newTreeMap(comparator());
        default:
          throw new AssertionError();
      }
    }
docs: Returns an empty mutable map whose keys will respect this {@link ElementOrder}.