If you set the TimeExtent property of your map, the request to the rest end point will be made by the framework behind the scene. That's the easier way. If for any reason you need to request yourself the rest end point. the timeinstant is the number of milliseconds since 1970 January, the 1st. So to convert a time to timeinstant, you can use code like:TimeSpan elapsed = timeToConvert.ToUniversalTime() - new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);long timeinstant = elapsed.TotalMilliseconds;
