* // Fall back to a secondary input stream in case of IOException.
   * ClosingFuture<InputStream> inputFuture =
   *     firstInputFuture.catchingAsync(
   *         IOException.class, (closer, x) -> secondaryInputStreamClosingFuture(), executor);
   * }
   * }</pre>
   *
   * <p>When selecting an executor, note that {@code directExecutor} is dangerous in some cases. See