});
    return holder.get();
  }

  /**
   * Updates the value currently associated with {@code key} by combining it with {@code x} via the
   * specified accumulator function, returning the new value. The previous value associated with
   * {@code key} (or zero, if there is none) is passed as the first argument to {@code
   * accumulatorFunction}, and {@code x} is passed as the second argument.
   *

	b.mu.Lock()
	defer b.mu.Unlock()

	// Check if exists already.
	if c, ok := b.caches[o.ID]; ok {
		c.lastHandout = time.Now()
		b.caches[o.ID] = c
		b.debugf("returning existing %v", o.ID)
		return c
	}

	if !o.Create {
		return metacache{
			id:     o.ID,
			bucket: o.Bucket,
			status: scanStateNone,
		}
	}

	// Create new and add.

	expected = updatedAtRe.ReplaceAllString(expected, `"updated_at"=?`)

	// ignore RETURNING "id" (only in PostgreSQL)
	returningRe := regexp.MustCompile(`(?i)RETURNING "id"`)
	actually = returningRe.ReplaceAllString(actually, ``)
	expected = returningRe.ReplaceAllString(expected, ``)

	actually = strings.TrimSpace(actually)
	expected = strings.TrimSpace(expected)

 *
 * <p>This class maintains a map of nodes to {@link GraphConnections}.
 *
 * <p>Collection-returning accessors return unmodifiable views: the view returned will reflect
 * changes to the graph (if the graph is mutable) but may not be modified by the user.
 *
 * <p>The time complexity of all collection-returning accessors is O(1), since views are returned.
 *
 * @author James Sexton
 * @author Joshua O'Madadhain

 * directed graphs, and an arbitrary endpoint of the edge on undirected graphs.
 *
 * <p>Collection-returning accessors return unmodifiable views: the view returned will reflect
 * changes to the graph (if the graph is mutable) but may not be modified by the user.
 *
 * <p>The time complexity of all collection-returning accessors is O(1), since views are returned.
 *
 * @author James Sexton
 * @author Joshua O'Madadhain

 * directed graphs, and an arbitrary endpoint of the edge on undirected graphs.
 *
 * <p>Collection-returning accessors return unmodifiable views: the view returned will reflect
 * changes to the graph (if the graph is mutable) but may not be modified by the user.
 *
 * <p>The time complexity of all collection-returning accessors is O(1), since views are returned.
 *
 * @author James Sexton
 * @author Joshua O'Madadhain

      assertEquals(RESULT_VALUE, f.get());
    }
    {
      MockExecutor mock = new MockExecutor();
      TestExecutor testExecutor = new TestExecutor(mock);
      Callable<String> task = Callables.returning(RESULT_VALUE);
      Future<String> f = testExecutor.submit(task);
      mock.assertLastMethodCalled("submit");
      assertEquals(RESULT_VALUE, f.get());
    }
  }

 *   }
 * }
 * return null; // Didn't find a preemptive auth scheme.
 * ```
 *
 * ## Reactive Authentication
 *
 * Implementations authenticate by returning a follow-up request that includes an authorization
 * header, or they may decline the challenge by returning null. In this case the unauthenticated
 * response will be returned to the caller that triggered it.
 *

   * Future} need not be {@linkplain Future#isDone done}, making {@code AsyncFunction} suitable for
   * asynchronous derivations.
   *
   * <p>Throwing an exception from this method is equivalent to returning a failing {@code Future}.
   */
  ListenableFuture<O> apply(@ParametricNullness I input) throws Exception;

It will use the default status code or the one you set in your *path operation*.

## Additional status codes { #additional-status-codes_1 }

If you want to return additional status codes apart from the main one, you can do that by returning a `Response` directly, like a `JSONResponse`, and set the additional status code directly.