/**
     * Contains the most recently submitted {@code Future}, which may be cancelled or updated,
     * always under a lock.
     */
    private static final class SupplantableFuture implements Cancellable {
      private final ReentrantLock lock;

      @GuardedBy("lock")
      private Future<@Nullable Void> currentFuture;

      SupplantableFuture(ReentrantLock lock, Future<@Nullable Void> currentFuture) {
        this.lock = lock;

   *       return value of this method as its cause
   * </ul>
   */
  public static
      Throwable tryInternalFastPathGetFailure(InternalFutureFailureAccess future) {
    return future.tryInternalFastPathGetFailure();
  }

  private InternalFutures() {}

    return delegate.submit(task);
  }

  @Override
  public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks)
      throws InterruptedException {
    Preconditions.checkNotNull(tasks, "tasks must not be null!");
    return delegate.invokeAll(tasks);
  }

  @Override
  public <T> List<Future<T>> invokeAll(
      Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)

    final AtomicLongMap<String> map = AtomicLongMap.create();

    ExecutorService threadPool = Executors.newFixedThreadPool(nThreads);
    ArrayList<Future<Long>> futures = new ArrayList<>();
    for (int i = 0; i < nTasks; i++) {
      futures.add(
          threadPool.submit(
              new Callable<Long>() {
                @Override
                public Long call() {
                  long threadSum = 0;

          }
        };

    AsyncCallable<String> asyncCallable =
        Callables.asAsyncCallable(callable, MoreExecutors.newDirectExecutorService());

    ListenableFuture<String> future = asyncCallable.call();
    assertSame(expected, future.get());
  }

  @J2ktIncompatible
  @GwtIncompatible
  public void testAsAsyncCallable_exception() throws Exception {
    final Exception expected = new IllegalArgumentException();

import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Queues;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import java.util.Deque;
import java.util.Map;
import java.util.concurrent.Executor;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicInteger;
import junit.framework.TestCase;

/**

      Callable<T> task,
      final BlockingQueue<Future<T>> queue) {
    final ListenableFuture<T> future = executorService.submit(task);
    future.addListener(
        new Runnable() {
          @Override
          public void run() {
            queue.add(future);
          }
        },
        directExecutor());
    return future;
  }

  /**

  }

  /**
   * Waits until the given future {@linkplain Future#isDone is done}, invoking the garbage collector
   * as necessary to try to ensure that this will happen.
   *
   * @throws RuntimeException if timed out or interrupted while waiting
   */
  @SuppressWarnings("removal") // b/260137033
  public static void awaitDone(Future<?> future) {
    if (future.isDone()) {
      return;
    }

import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Implementation of {@code Futures#withTimeout}.
 *

          }
        };

    AsyncCallable<String> asyncCallable =
        Callables.asAsyncCallable(callable, MoreExecutors.newDirectExecutorService());

    ListenableFuture<String> future = asyncCallable.call();
    assertSame(expected, future.get());
  }

  @J2ktIncompatible
  @GwtIncompatible
  public void testAsAsyncCallable_exception() throws Exception {
    final Exception expected = new IllegalArgumentException();