* - Favor responding to interrupts over timeouts.
   * - System.nanoTime() is expensive enough that we want to call it the minimum required number of
   *   times, typically once before invoking a blocking method. This often requires keeping track of
   *   the first time in a method that nanoTime() has been invoked, for which the special value 0L
   *   is reserved to mean "uninitialized". If timeout is non-positive, then nanoTime need never be

    if ((!features.contains(IteratorFeature.SUPPORTS_REMOVE) && removes > 1)
        || (stimuli.length >= 5 && removes > 2)) {
      // removes are the most expensive thing to test, since they often throw exceptions with stack
      // traces, so we test them a bit less aggressively
      return;
    }

    MultiExceptionListIterator reference = new MultiExceptionListIterator(expectedElements);

   * scattered in memory and thus don't interfere much with each
   * other. But Atomic objects residing in arrays will tend to be
   * placed adjacent to each other, and so will most often share
   * cache lines (with a huge negative performance impact) without
   * this precaution.
   *
   * In part because Cells are relatively large, we avoid creating

    if ((!features.contains(IteratorFeature.SUPPORTS_REMOVE) && removes > 1)
        || (stimuli.length >= 5 && removes > 2)) {
      // removes are the most expensive thing to test, since they often throw exceptions with stack
      // traces, so we test them a bit less aggressively
      return;
    }

    MultiExceptionListIterator reference = new MultiExceptionListIterator(expectedElements);

   * the entry from the Map. If another operation sees a zero in the map, it knows that the entry is
   * about to be removed, so this operation may remove it (often by replacing it with a new
   * AtomicInteger).
   */

  /** The number of occurrences of each element. */
  private final transient ConcurrentMap<E, AtomicInteger> countMap;

   *
   * @param lists the lists to choose elements from, in the order that the elements chosen from
   *     those lists should appear in the resulting lists
   * @param <B> any common base class shared by all axes (often just {@link Object})
   * @return the Cartesian product, as an immutable list containing immutable lists
   * @throws IllegalArgumentException if the size of the cartesian product would be greater than

   * scattered in memory and thus don't interfere much with each
   * other. But Atomic objects residing in arrays will tend to be
   * placed adjacent to each other, and so will most often share
   * cache lines (with a huge negative performance impact) without
   * this precaution.
   *
   * In part because Cells are relatively large, we avoid creating

  }

  /**
   * Clears fields that are no longer needed after this future has completed -- or at least all its
   * inputs have completed (more precisely, after {@link #handleAllCompleted()} has been called).
   * Often called multiple times (that is, both when the inputs complete and when the output
   * completes).
   *
   * <p>This is similar to our proposed {@code afterCommit} method but not quite the same. See the

      return "Functions.toStringFunction()";
    }
  }

  /**
   * Returns the identity function.
   *
   * <p><b>Discouraged:</b> Prefer using a lambda like {@code v -> v}, which is shorter and often
   * more readable.
   */
  // implementation is "fully variant"; E has become a "pass-through" type
  @SuppressWarnings("unchecked")
  public static <E extends @Nullable Object> Function<E, E> identity() {

   *
   * @param sets the sets to choose elements from, in the order that the elements chosen from those
   *     sets should appear in the resulting lists
   * @param <B> any common base class shared by all axes (often just {@link Object})
   * @return the Cartesian product, as an immutable set containing immutable lists
   * @throws NullPointerException if {@code sets}, any one of the {@code sets}, or any element of a