throw new IOException("reset not supported");
  }

  /**
   * Returns the {@link HashCode} based on the data read from this stream. The result is unspecified
   * if this method is called more than once on the same instance.
   */
  public HashCode hash() {
    return hasher.hash();
  }

  }

  data class CallStart(
    override val timestampNs: Long,
    override val call: Call,
  ) : CallEvent()

  data class CallEnd(
    override val timestampNs: Long,
    override val call: Call,
  ) : CallEvent() {
    override fun closes(event: CallEvent): Boolean = event is CallStart && call == event.call
  }

  data class CallFailed(

 * any type to which the event is assignable. This includes implemented interfaces, all
 * superclasses, and all interfaces implemented by superclasses.
 *
 * <p>When {@code post} is called, all registered subscribers for an event are run in sequence, so
 * subscribers should be reasonably quick. If an event may trigger an extended process (such as a

    int listenerCount = 20;
    CountDownLatch listenerLatch = new CountDownLatch(listenerCount);

    // Test that listeners added both before and after the value is available
    // get called correctly.
    for (int i = 0; i < 20; i++) {

      // Right in the middle start up a thread to close the latch.
      if (i == 10) {
        new Thread(() -> latch.countDown()).start();
      }

 *   <dt>{@link BiMap}
 *   <dd>An extension of {@link java.util.Map} that guarantees the uniqueness of its values as well
 *       as that of its keys. This is sometimes called an "invertible map," since the restriction on
 *       values enables it to support an {@linkplain BiMap#inverse inverse view} -- which is another
 *       instance of {@code BiMap}.
 *   <dt>{@link Table}

    @Override
    protected List<V> delegate() {
      return emptyList();
    }
  }

  @Override
  Iterator<Entry<K, V>> entryIterator() {
    throw new AssertionError("should never be called");
  }

  @Override
  Collection<Entry<K, V>> createEntries() {
    return new Entries();
  }

  @WeakOuter
  class Entries extends ForwardingCollection<Entry<K, V>> {
    @Override

    @Override
    protected List<V> delegate() {
      return emptyList();
    }
  }

  @Override
  Iterator<Entry<K, V>> entryIterator() {
    throw new AssertionError("should never be called");
  }

  @Override
  Collection<Entry<K, V>> createEntries() {
    return new Entries();
  }

  @WeakOuter
  class Entries extends ForwardingCollection<Entry<K, V>> {
    @Override

 *   <dt>{@link BiMap}
 *   <dd>An extension of {@link java.util.Map} that guarantees the uniqueness of its values as well
 *       as that of its keys. This is sometimes called an "invertible map," since the restriction on
 *       values enables it to support an {@linkplain BiMap#inverse inverse view} -- which is another
 *       instance of {@code BiMap}.
 *   <dt>{@link Table}

    GcFinalization.awaitClear(classUsedByGetChecked);
  }

  /**
   * Loads {@link WillBeUnloadedException} in a separate {@code ClassLoader}, calls {@code
   * getChecked(future, WillBeUnloadedException.class)}, and returns the loader. The caller can then
   * test that the {@code ClassLoader} can still be GCed. The test amounts to a test that {@code
   * getChecked} holds no strong references to the class.
   */

            logger.info("Deleted completed document data. The execution time is {}ms.", systemHelper.getCurrentTimeAsLong() - execTime);
        }
    }

    /**
     * Forces all crawlers to stop immediately.
     * Sets the force stop flag and stops all active crawler instances.
     */
    private void forceStop() {
        systemHelper.setForceStop(true);
        if (crawlerList != null) {