* Collection<V>>} to {@code Map<K, List<V>>}.
   *
   * @since 15.0
   */
  @SuppressWarnings("unchecked")
  // safe by specification of ListMultimap.asMap()
  public static <K extends @Nullable Object, V extends @Nullable Object> Map<K, List<V>> asMap(
      ListMultimap<K, V> multimap) {
    return (Map<K, List<V>>) (Map<K, ?>) multimap.asMap();