Zendes Chat Metric "Chat ended - Timestamp" for Explore

This would be fantastic, it's still missing. I was told by support I have to write my own custom attribute from scratch to get this figure. 

We still do not have this metric to be able to report to. More than 2 years since the first request was made for a metric which should have been there at the very beginning itself. This is a request to resolve something which should have been out of the box.