// Fesen Client
    //

    /**
     * Gets the thread pool used by the client.
     *
     * @return the thread pool
     */
    @Override
    public ThreadPool threadPool() {
        return client.threadPool();
    }

    /**
     * Gets the admin client for cluster and index administration.
     *
     * @return the admin client
     */
    @Override

 *
 * {@snippet :
 * ListenableFuture<Boolean> adminIsLoggedIn =
 *     FluentFuture.from(usersDatabase.getAdminUser())
 *         .transform(User::getId, directExecutor())
 *         .transform(ActivityService::isLoggedIn, threadPool)
 *         .catching(RpcException.class, e -> false, directExecutor());
 * }
 *
 * <h3>Alternatives</h3>
 *
 * <h4>Frameworks</h4>
 *