In Coresight, how can I display the average value of a tag over the selected time span. For instance, if the user selects the last 8h, I want to display the average of a tag's value (time weighted average) over the last 8h. If they change the time range to something else, say 03/1/2016-05/23/2016, I want to display the average of the tag during that time. With AF analytics it seems like I only can do pre-selected time spans (the last day, or last month, etc.). How can I allow for any dynamic time range?