*     arbitrary number of temporary directories, you might have to generate multiple directory
   *     names in a loop until {@code mkdir()} returns {@code true}.) For JRE users, prefer {@link
   *     java.nio.file.Files#createTempDirectory}, transforming it to a {@link File} using {@link
   *     java.nio.file.Path#toFile() toFile()} if needed. To restrict permissions as this method

   * java.util.function.Function) Collectors.toMap(Function, Function)}, which throws an {@code
   * IllegalStateException}.)
   *
   * @since 33.2.0 (available since 21.0 in guava-jre)
   */
  @IgnoreJRERequirement // Users will use this only if they're already using streams.
  public static <T extends @Nullable Object, K extends Enum<K>, V>
      Collector<T, ?, ImmutableMap<K, V>> toImmutableEnumMap(

   * resulting set will iterate over elements in their enum definition order, not encounter order.
   *
   * @since 33.2.0 (available since 21.0 in guava-jre)
   */
  @IgnoreJRERequirement // Users will use this only if they're already using streams.
  public static <E extends Enum<E>> Collector<E, ?, ImmutableSet<E>> toImmutableEnumSet() {