* For restrictions, please refer to the documentation of the then() method.
 */
public interface ListenableFuture<V extends @Nullable Object> extends Future<V>, IThenable<V> {
  void addListener(Runnable listener, Executor executor);

  /** Note that this method is not expected to be overridden. */
  @JsMethod
  @Override
  default <R extends @Nullable Object> IThenable<R> then(

  private var writer = Http2Writer(bytesOut, client)
  private val outFrames: MutableList<OutFrame> = ArrayList()
  private val inFrames: BlockingQueue<InFrame> = LinkedBlockingQueue()
  private var port = 0
  private val executor = Executors.newSingleThreadExecutor(threadFactory("MockHttp2Peer"))
  private var serverSocket: ServerSocket? = null
  private var socket: Socket? = null

  fun setClient(client: Boolean) {
    if (this.client == client) return

  /**
   * Wraps a {@code Callable} for submission to the underlying executor. This method is also applied
   * to any {@code Runnable} passed to the default implementation of {@link #wrapTask(Runnable)}.
   */
  protected abstract <T extends @Nullable Object> Callable<T> wrapTask(Callable<T> callable);

  /**
   * Wraps a {@code Runnable} for submission to the underlying executor. The default implementation
   * delegates to {@link #wrapTask(Callable)}.

import com.google.common.util.concurrent.AbstractFutureBenchmarks.Facade;
import com.google.common.util.concurrent.AbstractFutureBenchmarks.Impl;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.Executor;
import org.jspecify.annotations.NullUnmarked;

/** Measures the size of AbstractFuture implementations. */
@NullUnmarked
public class AbstractFutureFootprintBenchmark {

  enum State {
    NOT_DONE,

    executor.shutdown();
    assertTrue(executor.isShutdown());
    assertThrows(RejectedExecutionException.class, () -> executor.submit(doNothingRunnable));
    assertFalse(executor.isTerminated());

    // WAIT #2
    barrier.await(1, SECONDS);
    assertFalse(executor.awaitTermination(20, MILLISECONDS));

    // WAIT #3
    barrier.await(1, SECONDS);
    assertTrue(executor.awaitTermination(1, SECONDS));

                  + runnable
                  + " with executor "
                  + executor,
              e);
    }
  }

  private static final class RunnableExecutorPair {
    final Runnable runnable;
    final Executor executor;
    @Nullable RunnableExecutorPair next;

    RunnableExecutorPair(
        Runnable runnable, Executor executor, @Nullable RunnableExecutorPair next) {

        int iterations = 1000;
        ExecutorService executor = Executors.newFixedThreadPool(2);
        CountDownLatch endLatch = new CountDownLatch(2);
        AtomicInteger successCount = new AtomicInteger(0);
        List<Exception> exceptions = Collections.synchronizedList(new ArrayList<>());

        // Thread 1: Continuously adds trees
        executor.submit(() -> {
            try {

                  + runnable
                  + " with executor "
                  + executor,
              e);
    }
  }

  private static final class RunnableExecutorPair {
    final Runnable runnable;
    final Executor executor;
    @Nullable RunnableExecutorPair next;

    RunnableExecutorPair(
        Runnable runnable, Executor executor, @Nullable RunnableExecutorPair next) {

   */
  public static <V extends @Nullable Object> ListenableFuture<V> listenInPoolThread(
      Future<V> future, Executor executor) {
    checkNotNull(executor);
    if (future instanceof ListenableFuture) {
      return (ListenableFuture<V>) future;
    }
    return new ListenableFutureAdapter<>(future, executor);
  }

  /**
   * An adapter to turn a {@link Future} into a {@link ListenableFuture}. This will wait on the

      assertEquals(Service.State.STOPPING, state());
      shutdownCalled++;
    }

    @Override
    protected Executor executor() {
      return executor;
    }

    @Override
    public void tearDown() throws Exception {
      executor.shutdown();
    }
  }