/// <summary>
        /// <see cref="MyCompany.Travel.Client.ITravelAttachmentService"/>
        /// </summary>
        /// <param name="travelAttachment"><see cref="MyCompany.Travel.Client.ITravelAttachmentService"/></param>
        /// <returns><see cref="MyCompany.Travel.Client.ITravelAttachmentService"/></returns>
        public async Task Update(TravelAttachment travelAttachment)
        {
            string url = String.Format(CultureInfo.InvariantCulture
                                       , "{0}api/travelattachments", _urlPrefix);

            await base.PutAsync <TravelAttachment>(url, travelAttachment);
        }
        /// <summary>
        /// <see cref="MyCompany.Travel.Client.ITravelAttachmentService"/>
        /// </summary>
        /// <param name="travelAttachment"><see cref="MyCompany.Travel.Client.ITravelAttachmentService"/></param>
        /// <returns><see cref="MyCompany.Travel.Client.ITravelAttachmentService"/></returns>
        public async Task <int> Add(TravelAttachment travelAttachment)
        {
            string url = String.Format(CultureInfo.InvariantCulture
                                       , "{0}api/travelattachments/add", _urlPrefix);

            return(await base.PostAsync <int, TravelAttachment>(url, travelAttachment));
        }