// is undefined in shutdown hooks.
                    // This is because the logging code installs a shutdown hook of its
                    // own. See Cleaner class inside {@link LogManager}.
                    service.shutdown();
                    service.awaitTermination(terminationTimeout, timeUnit);
                  } catch (InterruptedException ignored) {

   * has consumed the entire input and they are ready to output a {@code HashCode}. The order of the
   * hashers are the same order as the functions given to the constructor.
   */
  // this could be cleaner if it passed HashCode[], but that would create yet another array...
  /* protected */ abstract HashCode makeHash(Hasher[] hashers);

  @Override
  public Hasher newHasher() {

 *       code, or even to discover <i>any</i> two distinct inputs that yield the same result. These
 *       are called <i>cryptographic hash functions</i>. But, whenever it is learned that either of
 *       these feats has become computationally feasible, the function is deemed "broken" and should
 *       no longer be used for secure purposes. (This is the likely eventual fate of <i>all</i>

              /*
               * requireNonNull is safe because we've initialized these if
               * !GENERATE_CANCELLATION_CAUSES.
               *
               * TODO(cpovirk): Maybe it would be cleaner to define a CancellationSupplier interface
               * with two implementations, one that contains causeless Cancellation instances and

 * Stats}, {@link PairedStatsAccumulator}, and {@link PairedStats}.
 *
 * @author Pete Gillin
 */
class StatsTesting {
  // TODO(cpovirk): Convince myself that this larger error makes sense.
  static final double ALLOWED_ERROR = isAndroid() ? .25 : 1e-10;

  // Inputs and their statistics:

  static final double ONE_VALUE = 12.34;

  static final double OTHER_ONE_VALUE = -56.78;

 *       amounts of computation (creating a thread, calling a few methods, etc) needed to reach a
 *       timeout point. Similarly, a SMALL is always discriminable as larger than SHORT and smaller
 *       than MEDIUM. And so on. These constants are set to conservative values, but even so, if
 *       there is ever any doubt, they can all be increased in one spot to rerun tests on slower

      throw new SkipThisScenarioException();
    }
  }

  // This exclusion doesn't exclude the TOMBSTONE objects we set. So 'done' NEW futures will look
  // larger than they are.
  @SuppressWarnings("FutureReturnValueIgnored")
  @Footprint(exclude = {Runnable.class, Executor.class, Thread.class, Exception.class})
  public Object measureSize() {
    for (Thread thread : blockedThreads) {

      throw new SkipThisScenarioException();
    }
  }

  // This exclusion doesn't exclude the TOMBSTONE objects we set. So 'done' NEW futures will look
  // larger than they are.
  @SuppressWarnings("FutureReturnValueIgnored")
  @Footprint(exclude = {Runnable.class, Executor.class, Thread.class, Exception.class})
  public Object measureSize() {
    for (Thread thread : blockedThreads) {

 * features}, the features supported by the iterator; and {@code expectedElements}, the elements the
 * iterator should return in order.
 *
 * <p>The items in {@code elementsToInsert} will be repeated if {@code steps} is larger than the
 * number of provided elements.
 *
 * @author Chris Povirk
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class ListIteratorTester<E extends @Nullable Object>

 * features}, the features supported by the iterator; and {@code expectedElements}, the elements the
 * iterator should return in order.
 *
 * <p>The items in {@code elementsToInsert} will be repeated if {@code steps} is larger than the
 * number of provided elements.
 *
 * @author Chris Povirk
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class ListIteratorTester<E extends @Nullable Object>