/// <summary>
        /// Gets the API URL.
        /// </summary>
        /// <param name="handler">The handler.</param>
        /// <param name="queryString">The query string.</param>
        /// <returns>System.String.</returns>
        /// <exception cref="System.ArgumentNullException">handler</exception>
        public string GetApiUrl(string handler, QueryStringDictionary queryString)
        {
            if (string.IsNullOrEmpty(handler))
            {
                throw new ArgumentNullException("handler");
            }

            if (queryString == null)
            {
                throw new ArgumentNullException("queryString");
            }

            return(queryString.GetUrl(ApiUrl + "/" + handler));
        }