ExecutorService service, long terminationTimeout, TimeUnit timeUnit) {
    new Application().addDelayedShutdownHook(service, terminationTimeout, timeUnit);
  }

  /** Represents the current application to register shutdown hooks. */
  @J2ktIncompatible
  @GwtIncompatible // TODO
  @VisibleForTesting
  static class Application {

    final ExecutorService getExitingExecutorService(

   *       according to the definition of the equivalence. The hash need not remain consistent from
   *       one execution of an application to another execution of the same application.
   *   <li>It is <i>distributable across equivalence</i>: for any references {@code x} and {@code
   *       y}, if {@code equivalent(x, y)}, then {@code hash(x) == hash(y)}. It is <i>not</i>