public Set<Feature<? super @Nullable Void>> getImpliedFeatures() {
      return emptySet();
    }
  }

  /**
   * Creates a suite whose map has some elements filtered out of view.
   *
   * <p>Because the map may be ascending or descending, this test must derive the relative order of
   * these extreme values rather than relying on their regular sort ordering.
   */
  final TestSuite createSubmapSuite(

  protected Queue<String> create() {
    TestQueue<String> inner = new TestQueue<>();
    Queue<String> outer = Synchronized.queue(inner, inner.mutex);
    outer.add("foo"); // necessary because we try to remove elements later on
    return outer;
  }

  private static final class TestQueue<E> implements Queue<E> {
    private final Queue<E> delegate = Lists.newLinkedList();

   * add the suppression to the whole method (which turns off checking for a large section of code),
   * or extract a variable, and put the suppression on that. However, a local variable typically
   * doesn't work: Because nullness analyses typically infer the nullness of local variables,
   * there's no way to assign a {@code @Nullable T} to a field {@code T foo;} and instruct the

    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());
    assertFalse(task.isCancelled());

    // Start the task to put it in the RUNNING state.  Have to use a separate
    // thread because the task will block on the task latch after unblocking
    // the run latch.
    exec.execute(task);
    runLatch.await();
    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());

  /**
   * All node connections in this graph, in edge insertion order.
   *
   * <p>Note: This field and {@link #adjacentNodeValues} cannot be combined into a single
   * LinkedHashMap because one target node may be mapped to both a predecessor and a successor. A
   * LinkedHashMap combines two such edges into a single node-value pair, even though the edges may
   * not have been inserted consecutively.
   */

    };

    static final String[] WINERR_MESSAGES = {
        "The operation completed successfully.", "Access is denied.",
        "No more connections can be made to this remote computer at this time because there are already as many connections as the computer can accept.",
        "The pipe state is invalid.", "All pipe instances are busy.", "The pipe is being closed.", "No process is on the other end of the pipe.",

    val attempt2 = attempt1.nextConnectionSpec(connectionSpecs, socket)
    assertThat(attempt2).isNull()
    socket.close()

    // sslV3 is not used because SSLv3 is not enabled on the socket.
  }

  private fun createSocketWithEnabledProtocols(vararg tlsVersions: TlsVersion): SSLSocket {
    return (handshakeCertificates.sslSocketFactory().createSocket() as SSLSocket).apply {

   * {@link PermittedMetaException} instances, which wrap a set of all exceptions that the iterator
   * could throw during the invocation of that method. This is necessary because, e.g., a call to
   * {@code iterator().remove()} of an unmodifiable list could throw either {@link
   * IllegalStateException} or {@link UnsupportedOperationException}. Note that iterator

   *
   * <p>If {@code googleOptional} is known to be non-null, use {@code googleOptional.toJavaUtil()}
   * instead.
   *
   * <p>Unfortunately, the method reference {@code Optional::toJavaUtil} will not work, because it
   * could refer to either the static or instance version of this method. Write out the lambda
   * expression {@code o -> Optional.toJavaUtil(o)} instead.
   *
   * @since NEXT (but since 21.0 in the JRE flavor)

  private final ListenerCallQueue<Listener> listeners = new ListenerCallQueue<>();

  /**
   * The current state of the service. This should be written with the lock held but can be read
   * without it because it is an immutable object in a volatile field. This is desirable so that
   * methods like {@link #state}, {@link #failureCause} and notably {@link #toString} can be run
   * without grabbing the lock.
   *