*
   * @throws IllegalStateException if multiple charset values have been set for this media type
   * @throws IllegalCharsetNameException if a charset value is present, but illegal
   * @throws UnsupportedCharsetException if a charset value is present, but no support is available
   *     in this instance of the Java virtual machine
   */
  public Optional<Charset> charset() {

    this.executor = bus.executor();
  }

  /** Dispatches {@code event} to this subscriber using the proper executor. */
  final void dispatchEvent(Object event) {
    executor.execute(
        () -> {
          try {
            invokeSubscriberMethod(event);
          } catch (InvocationTargetException e) {
            bus.handleSubscriberException(e.getCause(), context(event));
          }
        });
  }

  /**

import java.lang.annotation.Target;

/**
 * Marks a method as an event subscriber.
 *
 * <p>The type of event will be indicated by the method's first (and only) parameter, which cannot
 * be primitive. If this annotation is applied to methods with zero parameters, or more than one
 * parameter, the object containing the method will not be able to register for event delivery from
 * the {@link EventBus}.
 *

   *
   * <p>TODO: b/147144588 - We are currently also missing the methods inherited from {@link
   * AnnotatedElement}, which {@code TypeVariable} began to extend only in Java 8. Those methods
   * refer only to types present under Android, so we could implement them in {@code
   * TypeVariableImpl} today. (We could probably then make {@code TypeVariableImpl} implement {@code
   * AnnotatedElement} so that we get partial compile-time checking.)
   *

   *
   * @param identifier short name for the bus, for logging purposes.
   * @param executor Executor to use to dispatch events. It is the caller's responsibility to shut
   *     down the executor after the last event has been posted to this event bus.
   */
  public AsyncEventBus(String identifier, Executor executor) {
    super(identifier, executor, Dispatcher.legacyAsync(), LoggingHandler.INSTANCE);
  }

  /**

    to use the modified definitions.)

    b) Use a suitable shared library mechanism for linking with the
    Library.  A suitable mechanism is one that (1) uses at run time a
    copy of the library already present on the user's computer system,
    rather than copying library functions into the executable, and (2)
    will operate properly with a modified version of the library, if

                break;
            case CALLED_NOT_PRESENT:
                result.append("Called name not present");
                break;
            case NO_RESOURCES:
                result.append("Called name present, but insufficient resources");
                break;
            case UNSPECIFIED:
                result.append("Unspecified error");
                break;

import java.lang.annotation.Target;

/**
 * Marks a method as an event subscriber.
 *
 * <p>The type of event will be indicated by the method's first (and only) parameter, which cannot
 * be primitive. If this annotation is applied to methods with zero parameters, or more than one
 * parameter, the object containing the method will not be able to register for event delivery from
 * the {@link EventBus}.
 *

     *
     * @return The version number, or null if not versioned
     */
    Long getVersionNo();

    /**
     * Converts this search log event to a source map for indexing or logging.
     *
     * @return Map representation of the event data
     */
    Map<String, Object> toSource();

    /**
     * Gets the type of this search log event.
     *

  private static final ListenerCallQueue.Event<Listener> TERMINATED_FROM_NEW_EVENT =
      terminatedEvent(NEW);
  private static final ListenerCallQueue.Event<Listener> TERMINATED_FROM_STARTING_EVENT =
      terminatedEvent(STARTING);
  private static final ListenerCallQueue.Event<Listener> TERMINATED_FROM_RUNNING_EVENT =
      terminatedEvent(RUNNING);
  private static final ListenerCallQueue.Event<Listener> TERMINATED_FROM_STOPPING_EVENT =