* allowing dispatch to occur asynchronously.
 *
 * @author Cliff Biffle
 * @since 10.0
 */
@ElementTypesAreNonnullByDefault
public class AsyncEventBus extends EventBus {

  /**
   * Creates a new AsyncEventBus that will use {@code executor} to dispatch events. Assigns {@code
   * identifier} as the bus's name for logging purposes.
   *

    return new PerThreadQueuedDispatcher();
  }

  /**
   * Returns a dispatcher that queues events that are posted in a single global queue. This behavior
   * matches the original behavior of AsyncEventBus exactly, but is otherwise not especially useful.
   * For async dispatch, an {@linkplain #immediate() immediate} dispatcher should generally be
   * preferable.
   */
  static Dispatcher legacyAsync() {