*             executor)
 *         .transformAsync((closer, transaction) -> transaction.queryClosingFuture("..."), executor)
 *         .transform((closer, result) -> result.get("userName"), directExecutor())
 *         .catching(DBException.class, e -> "no user", directExecutor())
 *         .finishToFuture();
 * }
 *
 * In this example, when the {@code userName} {@link Future} is done, the transaction and the query

   * ListenableFuture<Integer> faultTolerantFuture = Futures.catching(
   *     fetchCounterFuture, FetchException.class, x -> 0, directExecutor());
   * }
   *
   * <p>When selecting an executor, note that {@code directExecutor} is dangerous in some cases. See
   * the warnings the {@link MoreExecutors#directExecutor} documentation.
   *
   * @param input the primary input {@code Future}