*
   * @param event event to post.
   */
  public void post(Object event) {
    Iterator<Subscriber> eventSubscribers = subscribers.getSubscribers(event);
    if (eventSubscribers.hasNext()) {
      dispatcher.dispatch(event, eventSubscribers);
    } else if (!(event instanceof DeadEvent)) {
      // the event had no subscribers and was not itself a DeadEvent
      post(new DeadEvent(this, event));
    }
  }

   * all subscribers in the order they are posted.
   *
   * <p>When all subscribers are dispatched to using a <i>direct</i> executor (which dispatches on
   * the same thread that posts the event), this yields a breadth-first dispatch order on each
   * thread. That is, all subscribers to a single event A will be called before any subscribers to

    bus.register(compCatcher);

    // Two additional event types: Object and Comparable<?> (played by Integer)
    Object objEvent = new Object();
    Object compEvent = 6;

    bus.post(EVENT);
    bus.post(objEvent);
    bus.post(compEvent);

    // Check the StringCatcher...
    List<String> stringEvents = stringCatcher.getEvents();
    assertEquals("Only one String should be delivered.", 1, stringEvents.size());

    bus.register(compCatcher);

    // Two additional event types: Object and Comparable<?> (played by Integer)
    Object objEvent = new Object();
    Object compEvent = 6;

    bus.post(EVENT);
    bus.post(objEvent);
    bus.post(compEvent);

    // Check the StringCatcher...
    List<String> stringEvents = stringCatcher.getEvents();
    assertEquals("Only one String should be delivered.", 1, stringEvents.size());

  @GwtIncompatible // SerializableTester
  public void testIsNull_serialization() {
    Predicate<String> pre = Predicates.isNull();
    Predicate<String> post = SerializableTester.reserializeAndAssert(pre);
    assertEquals(pre.apply("foo"), post.apply("foo"));
    assertEquals(pre.apply(null), post.apply(null));
  }

  public void testNotNull_apply() {
    Predicate<@Nullable Integer> notNull = Predicates.notNull();

      </plugin>
      <plugin>
        <artifactId>maven-source-plugin</artifactId>
        <executions>
          <execution>
            <id>attach-test-sources</id>
            <phase>post-integration-test</phase>
            <goals><goal>test-jar</goal></goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <artifactId>maven-jar-plugin</artifactId>

      </plugin>
      <plugin>
        <artifactId>maven-source-plugin</artifactId>
        <executions>
          <execution>
            <id>attach-test-sources</id>
            <phase>post-integration-test</phase>
            <goals><goal>test-jar</goal></goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <artifactId>maven-surefire-plugin</artifactId>

     * already have to deal with, thanks to DI frameworks that perform field and method injection,
     * frameworks like Android that define post-construct hooks like Activity.onCreate, etc.
     */

    @CheckForNull private ValueSetLink<K, V> predecessorInValueSet;
    @CheckForNull private ValueSetLink<K, V> successorInValueSet;

  }

  public void testToString() {
    // With ports.
    assertEquals("foo:101", "" + HostAndPort.fromString("foo:101"));
    assertEquals(":102", HostAndPort.fromString(":102").toString());
    assertEquals("[1::2]:103", HostAndPort.fromParts("1::2", 103).toString());
    assertEquals("[::1]:104", HostAndPort.fromString("[::1]:104").toString());

    // Without ports.
    assertEquals("foo", "" + HostAndPort.fromString("foo"));

 * could in principle cause problems for some users. Still, we expect that the benefits of the
 * nullness annotations in particular will outweigh the costs. (And it's worth noting that we have
 * released multiple ListenableFuture.class files that are not byte-for-byte compatible even from
 * the beginning, thanks to using different `-source -target` values for compiling our `-jre` and