*         .catching(DBException.class, e -> "no user", directExecutor())
 *         .finishToFuture();
 * }
 *
 * In this example, when the {@code userName} {@link Future} is done, the transaction and the query
 * result cursor will both be closed, even if the operation is cancelled or fails.
 *
 * <h4>Manually closing</h4>
 *
 * If you want to close the captured objects manually, after you've used the final result, call