* asynchronous only if {@link CacheLoader#reload} was overridden with an asynchronous
   * implementation.
   *
   * <p>Returns without doing anything if another thread is currently loading the value for {@code
   * key}. If the cache loader associated with this cache performs refresh asynchronously then this
   * method may return before refresh completes.
   *

   * asynchronous only if {@link CacheLoader#reload} was overridden with an asynchronous
   * implementation.
   *
   * <p>Returns without doing anything if another thread is currently loading the value for {@code
   * key}. If the cache loader associated with this cache performs refresh asynchronously then this
   * method may return before refresh completes.
   *

   * set (including {@linkplain #setFuture set asynchronously}). When a call to this method returns,
   * the {@code Future} is guaranteed to be {@linkplain #isDone done} <b>only if</b> the call was
   * accepted (in which case it returns {@code true}). If it returns {@code false}, the {@code
   * Future} may have previously been set asynchronously, in which case its result may not be known

    final NoOpService service1 = new NoOpService();
    // This service will start service1 when addListener is called.  This simulates service1 being
    // started asynchronously.
    Service service2 =
        new Service() {
          final NoOpService delegate = new NoOpService();

          @Override
          public final void addListener(Listener listener, Executor executor) {

    final NoOpService service1 = new NoOpService();
    // This service will start service1 when addListener is called.  This simulates service1 being
    // started asynchronously.
    Service service2 =
        new Service() {
          final NoOpService delegate = new NoOpService();

          @Override
          public final void addListener(Listener listener, Executor executor) {

    return (FluentFuture<V>) Futures.withTimeout(this, timeout, unit, scheduledExecutor);
  }

  /**
   * Returns a new {@code Future} whose result is asynchronously derived from the result of this
   * {@code Future}. If the input {@code Future} fails, the returned {@code Future} fails with the
   * same exception (and the function is not invoked).
   *

 *         } catch (TimeoutException timeout) {
 *           // stopping timed out
 *         }
 *       }
 *     });
 *     manager.startAsync();  // start all the services asynchronously
 *   }
 * }
 * }</pre>
 *
 * <p>This class uses the ServiceManager's methods to start all of its services, to respond to

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A step in a pipeline of an asynchronous computation. When the last step in the computation is
 * complete, some objects captured during the computation are closed.
 *
 * <p>A pipeline of {@code ClosingFuture}s is a tree of steps. Each step represents either an
 * asynchronously-computed intermediate value, or else an exception that indicates the failure or

   * CacheBuilder#refreshAfterWrite}, or through a call to {@link LoadingCache#refresh}.
   *
   * <p>This implementation synchronously delegates to {@link #load}. It is recommended that it be
   * overridden with an asynchronous implementation when using {@link
   * CacheBuilder#refreshAfterWrite}.
   *
   * <p><b>Note:</b> <i>all exceptions thrown by this method will be logged and then swallowed</i>.

    if (delegate.isDone()) {
      return delegate;
    }
    return TimeoutFuture.create(delegate, time, unit, scheduledExecutor);
  }

  /**
   * Returns a new {@code Future} whose result is asynchronously derived from the result of the
   * given {@code Future}. If the given {@code Future} fails, the returned {@code Future} fails with
   * the same exception (and the function is not invoked).
   *