public void shutdown() {
        shutdownListener.onShutdown();
    }

    public void addShutdownListener(final ShutdownListener listener) {
        shutdownListener = listener;
    }

    public interface ShutdownListener {
        void onShutdown();
    }

  }

  @Override
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public void addListener(Runnable listener, Executor executor) {
    checkNotNull(listener, "Runnable was null.");
    checkNotNull(executor, "Executor was null.");
    try {
      executor.execute(listener);
    } catch (Exception e) { // sneaky checked exception

 * guaranteed to execute. There is no guarantee, however, that listeners will be executed in the
 * order that they are added.
 *
 * <p>Exceptions thrown by a listener will be propagated up to the executor. Any exception thrown
 * during {@code Executor.execute} (e.g., a {@code RejectedExecutionException} or an exception

                    listener.sessionStarted(event);
                    break;
                case SessionEnded:
                    listener.sessionEnded(event);
                    break;

                case ProjectSkipped:
                    listener.projectSkipped(event);
                    break;
                case ProjectStarted:
                    listener.projectStarted(event);
                    break;

            final ClassRealm realm,
            final ConfigurationListener listener)
            throws ComponentConfigurationException {
        try {
            ClassRealmConverter.pushContextRealm(realm);

            this.configureComponent(component, configuration, evaluator, (ClassLoader) realm, listener);
        } finally {
            ClassRealmConverter.popContextRealm();
        }
    }

/**
 * Defines events that the model builder fires during construction of the effective model. When a listener encounters
 * errors while processing the event, it can report these problems via {@link ModelBuildingEvent#problems()}.
 */
public interface ModelBuildingListener {

    /**
     * Notifies the listener that the model has been constructed to the extent where build extensions can be processed.
     *

    void call(L listener);
  }

  /**
   * Adds a listener that will be called using the given executor when events are later {@link
   * #enqueue enqueued} and {@link #dispatch dispatched}.
   */
  public void addListener(L listener, Executor executor) {
    checkNotNull(listener, "listener");
    checkNotNull(executor, "executor");
    listeners.add(new PerListenerQueue<>(listener, executor));
  }

  /**

        for (ProjectExecutionListener listener : listeners) {
            listener.beforeProjectExecution(event);
        }
    }

    @Override
    public void beforeProjectLifecycleExecution(ProjectExecutionEvent event) throws LifecycleExecutionException {
        for (ProjectExecutionListener listener : listeners) {
            listener.beforeProjectLifecycleExecution(event);
        }
    }

                    InternalMavenSession.from(ee.getSession().getSession());
            Collection<Listener> listeners = session.getListeners();
            if (!listeners.isEmpty()) {
                Event event = new DefaultEvent(session, ee);
                for (Listener listener : listeners) {
                    listener.onEvent(event);
                }
            }
        }
    }

    @Override

  }

  @Override
  public final State state() {
    return delegate.state();
  }

  /** @since 13.0 */
  @Override
  public final void addListener(Listener listener, Executor executor) {
    delegate.addListener(listener, executor);
  }

  /** @since 14.0 */
  @Override
  public final Throwable failureCause() {
    return delegate.failureCause();
  }

  /** @since 15.0 */