Thread th = new Thread(() -> {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException ignore) {}
            deferred.reject(new Exception());
        });
        th.start();

        final CountDownLatch latch = new CountDownLatch(1);
        deferred.promise().error(error -> latch.countDown());

 *   It is similar to a Promise in JavaScript.
 *   It allows you to register callbacks that will be executed when the computation is complete,
 *   either successfully (resolve) or with an error (reject).
 * </p>
 *
 * <p>
 *   The Deferred class has a Promise inner class that allows you to register callbacks
 *   to be executed when the computation is complete.

                    deferred.reject(new SuggesterException("Search failure. Failed shards num:" + searchResponse.getFailedShards()));
                } else {
                    deferred.resolve(createResponse(searchResponse));
                }
            }

            @Override
            public void onFailure(final Exception e) {
                deferred.reject(e);
            }
        });
    }

        }
        return deferred.promise();
    }

    /**
     * Processes the request.
     * @param client The OpenSearch client.
     * @param deferred The Deferred object to resolve or reject the response.
     */
    protected abstract void processRequest(Client client, Deferred<T> deferred);

    /**
     * Returns a validation error message, or null if there are no errors.