Executor executor) {
    return AbstractCatchingFuture.createAsync(input, exceptionType, fallback, executor);
  }

  /**
   * Returns a future that delegates to another but will finish early (via a {@link
   * TimeoutException} wrapped in an {@link ExecutionException}) if the specified duration expires.
   *
   * <p>The delegate future is interrupted and cancelled if it times out.
   *

func listPathRaw(ctx context.Context, opts listPathRawOptions) (err error) {
	disks := opts.disks
	if len(disks) == 0 {
		return fmt.Errorf("listPathRaw: 0 drives provided")
	}

	// Cancel upstream if we finish before we expect.
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	// Keep track of fallback disks
	var fdMu sync.Mutex
	fds := opts.fallbackDisks
	fallback := func(err error) StorageAPI {

    // give the third get a chance to run; it is okay for this to be racy
    // as the end result should be the same either way
    fourthSignal.await();
    Thread.yield();

    // let computation finish
    computeSignal.countDown();
    doneSignal.await();

    assertThat(callCount.get()).isEqualTo(1);
    assertThat(result.get(0)).isEqualTo("barfoo");
    assertThat(result.get(1)).isEqualTo("barfoo");

and walking away.  `You insult me by talking such nonsense!'

  `I didn't mean it!' pleaded poor Alice.  `But you're so easily
offended, you know!'

  The Mouse only growled in reply.

  `Please come back and finish your story!' Alice called after
it; and the others all joined in chorus, `Yes, please do!' but
the Mouse only shook its head impatiently, and walked a little
quicker.

Worse, there is no guarantee that the write to <code>done</code> will ever
be observed by <code>main</code>, since there are no synchronization
events between the two threads.  The loop in <code>main</code> is not
guaranteed to finish.
</p>

<p>
There are subtler variants on this theme, such as this program.
</p>

<pre>
type T struct {
	msg string
}

var g *T

func setup() {
	t := new(T)

    // give the third get a chance to run; it is okay for this to be racy
    // as the end result should be the same either way
    fourthSignal.await();
    Thread.yield();

    // let computation finish
    computeSignal.countDown();
    doneSignal.await();

    assertThat(callCount.get()).isEqualTo(1);
    assertThat(result.get(0)).isEqualTo("barfoo");
    assertThat(result.get(1)).isEqualTo("barfoo");

   * computes or retrieves it using the supplied {@code CacheLoader}. If another thread is currently
   * loading the value for this key, simply waits for that thread to finish and returns its loaded
   * value. Note that multiple threads can concurrently load values for distinct keys.
   *
   * <p>This method does not alter the state of this {@code CacheBuilder} instance, so it can be

			if disks[index] == nil {
				return errDiskNotFound
			}
			return disks[index].RenamePart(ctx, srcBucket, srcEntry, dstBucket, dstEntry, optsMeta, skipParent)
		}, index)
	}

	// Wait for all renames to finish.
	errs := g.Wait()

	err := reduceWriteQuorumErrs(ctx, errs, objectOpIgnoredErrs, writeQuorum)
	if err != nil {
		er.cleanupMultipartPath(ctx, paths...)
	}

   * computes or retrieves it using the supplied {@code CacheLoader}. If another thread is currently
   * loading the value for this key, simply waits for that thread to finish and returns its loaded
   * value. Note that multiple threads can concurrently load values for distinct keys.
   *
   * <p>This method does not alter the state of this {@code CacheBuilder} instance, so it can be

    peer.play()

    // Play it back.
    val connection = connect(peer)
    connection.writePingAndAwaitPong()
    val stream = connection.newStream(headerEntries("a", "android"), true)
    // finish the stream
    stream.writeHeaders(headerEntries("b", "berserk"), true, false)
    assertFailsWith<IllegalStateException> {
      stream.enqueueTrailers(headersOf("trailers", "boom"))
    }
  }