/// <summary>
        /// Creates a bulk job under the specified account.
        /// </summary>
        /// <param name="accountId">Account ID.</param>
        /// <param name="createBulkJob">CreateBulkJob.</param>
        /// <param name="client">REST client.</param>
        /// <returns>Bulk Job ID</returns>
        private static string CreateBulkJob(int accountId, CreateBulkJob createBulkJob, IVcRestClient client = null)
        {
            string  content = CreateRawContent(BuildCreateBulkJobUrl(accountId), createBulkJob, client);
            JObject json    = JObject.Parse(content);

            return(json.First.First.ToString());
        }
        /// <summary>
        /// Creates a bulk job under the specified account.
        /// </summary>
        /// <param name="accountId">Account ID.</param>
        /// <param name="toNumbers">To numbers.</param>
        /// <param name="fromNumber">From number.</param>
        /// <param name="connectorId">Connector ID.</param>
        /// <param name="body">Body.</param>
        /// <param name="mediaUrls">Media Urls.</param>
        /// <param name="client">REST clinet.</param>
        /// <returns>Bulk Job ID</returns>
        private static string CreateBulkJob(int accountId, List <string> toNumbers, string fromNumber = null, int?connectorId = null, string body = null, List <string> mediaUrls = null, IVcRestClient client = null)
        {
            CreateBulkJob createBulkJob = new CreateBulkJob(toNumbers)
            {
                FromNumber  = fromNumber,
                ConnectorId = connectorId,
                Body        = body,
                MediaUrls   = mediaUrls
            };

            return(CreateBulkJob(accountId, createBulkJob, client));
        }