if (remainingNanos + SPIN_THRESHOLD_NANOS < 0) {
      // We over-waited for our timeout.
      message += " (plus ";
      long overWaitNanos = -remainingNanos;
      long overWaitUnits = unit.convert(overWaitNanos, TimeUnit.NANOSECONDS);
      long overWaitLeftoverNanos = overWaitNanos - unit.toNanos(overWaitUnits);
      boolean shouldShowExtraNanos =

   *
   * <p>Note that if any input set is empty, the Cartesian product will also be empty. If no sets at
   * all are provided (an empty list), the resulting Cartesian product has one element, an empty
   * list (counter-intuitive, but mathematically consistent).
   *
   * <p><i>Performance notes:</i> while the cartesian product of sets of size {@code m, n, p} is a

@IgnoreJRERequirement // Users will use this only if they're already using streams.
@Beta // TODO: b/288085449 - Remove.
public final class MoreCollectors {

  /*
   * TODO(lowasser): figure out if we can convert this to a concurrent AtomicReference-based
   * collector without breaking j2cl?
   */
  private static final Collector<Object, ?, Optional<Object>> TO_OPTIONAL =
      Collector.of(
          ToOptionalState::new,

  }

  @J2ktIncompatible // MapMaker
  @VisibleForTesting
  static class ArbitraryOrdering extends Ordering<@Nullable Object> {

    private final AtomicInteger counter = new AtomicInteger(0);
    private final ConcurrentMap<Object, Integer> uids =
        Platform.tryWeakKeys(new MapMaker()).makeMap();

    private Integer getUid(Object obj) {
      Integer uid = uids.get(obj);

    /**
     * In the event of a setCount(elem, 0) call, we may need to remove elements, which destroys the
     * insertion order property of ObjectCountHashMap. In that event, we need to convert to a
     * ObjectCountLinkedHashMap, but we need to know we did that so we can convert back.
     */
    boolean isLinkedHash = false;

    /**
     * Creates a new builder. The returned builder is equivalent to the builder generated by {@link

  // whatever warnings might come along with it. :(

  /**
   * Returns an immutable list containing the given elements, in order.
   *
   * <p>The array {@code others} must not be longer than {@code Integer.MAX_VALUE - 12}.
   *
   * @throws NullPointerException if any element is null
   * @since 3.0 (source-compatible since 2.0)
   */

      this.bimap = checkNotNull(bimap);
    }

    @Override
    protected B doForward(A a) {
      return convert(bimap, a);
    }

    @Override
    protected A doBackward(B b) {
      return convert(bimap.inverse(), b);
    }

    private static <X, Y> Y convert(BiMap<X, Y> bimap, X input) {
      Y output = bimap.get(input);