/// <summary>
        /// Serializes the property to a Json value.
        /// </summary>
        /// <param name="service">The service.</param>
        /// <returns>
        /// A Json value (either a JsonObject, an array of Json values, or a Json primitive)
        /// </returns>
        internal override object InternalToJson(ExchangeService service)
        {
            JsonObject jsonProperty = new JsonObject();

            if (this.Start.HasValue)
            {
                jsonProperty.Add(XmlElementNames.StartDateTime, service.ConvertDateTimeToUniversalDateTimeString(this.Start.Value));
            }
            if (this.End.HasValue)
            {
                jsonProperty.Add(XmlElementNames.EndDateTime, service.ConvertDateTimeToUniversalDateTimeString(this.End.Value));
            }

            return(jsonProperty);
        }