/// <summary>
        /// Returns an array of all classifiers to the callback function.
        /// </summary>
        /// <param name="callback">The callback to invoke with the Classifiers object.</param>
        /// <returns>Returns true if the request is submitted.</returns>
        public bool GetClassifiers(OnGetClassifiers callback)
        {
            if (callback == null)
            {
                throw new ArgumentNullException("callback");
            }

            RESTConnector connector = RESTConnector.GetConnector(SERVICE_ID, "/v1/classifiers");

            if (connector == null)
            {
                return(false);
            }

            GetClassifiersReq req = new GetClassifiersReq();

            req.Callback   = callback;
            req.OnResponse = OnGetClassifiersResp;

            return(connector.Send(req));
        }