* keys and values are the result of applying the provided mapping functions to the input
   * elements.
   *
   * <p>If the mapped keys contain duplicates (according to the comparator), the values are merged
   * using the specified merging function. Entries will appear in the encounter order of the first
   * occurrence of the key.
   *
   * @since 33.2.0 (available since 21.0 in guava-jre)
   */

   * keys and values are the result of applying the provided mapping functions to the input
   * elements.
   *
   * <p>If the mapped keys contain duplicates (according to the comparator), the values are merged
   * using the specified merging function. Entries will appear in the encounter order of the first
   * occurrence of the key.
   *
   * @since 21.0
   */
  public static <T extends @Nullable Object, K, V>

   * powerSet(ImmutableSet.of(1, 2))} returns the set {@code {{}, {1}, {2}, {1, 2}}}.
   *
   * <p>Elements appear in these subsets in the same iteration order as they appeared in the input
   * set. The order in which these subsets appear in the outer set is undefined. Note that the power
   * set of the empty set is not the empty set, but a one-element set containing the empty set.
   *

   */
  abstract <T> T getFinalValue(ClosingFuture<T> closingFuture) throws ExecutionException;

  /** Marks the given step final, cancels it, and waits for the cancellation to happen. */
  abstract void cancelFinalStepAndWait(ClosingFuture<TestCloseable> closingFuture);

  /**
   * Marks the given step final and waits for it to fail. Expects the failure exception to match

   * function on that value. The resulting multimap is created as an immutable snapshot. In the
   * returned multimap, keys appear in the order they are first encountered, and the values
   * corresponding to each key appear in the same order as they are encountered.
   *
   * <p>For example,
   *
   * <pre>{@code
   * List<String> badGuys =

  }

  /**
   * Returns the corresponding primitive type if this is a wrapper type; otherwise returns {@code
   * this} itself. Idempotent.
   *
   * @since 15.0
   */
  public final TypeToken<T> unwrap() {
    if (isWrapper()) {
      @SuppressWarnings("unchecked") // this is a wrapper class
      Class<T> type = (Class<T>) runtimeType;
      return of(Primitives.unwrap(type));
    }

   */
  abstract <T> T getFinalValue(ClosingFuture<T> closingFuture) throws ExecutionException;

  /** Marks the given step final, cancels it, and waits for the cancellation to happen. */
  abstract void cancelFinalStepAndWait(ClosingFuture<TestCloseable> closingFuture);

  /**
   * Marks the given step final and waits for it to fail. Expects the failure exception to match