Cummulative sum regardless over time interval

I`m looking for a cummulative unique count in Kibana. I want to count unique users of an application over time. It´s not the unique count of each time bucket. Instead of sequential time buckets I need a bucket to have the same starting time, but an increasing ending time.

This topic was opend in October 2017 already: Cumulative Sum regardless of time interval

I do also know that in Elasticsearch 7.4 the aggregation cummulative cardinaltiy is realeased. But is there any work around available without this new aggregation?

I'm not aware of any workaround in Kibana for this right now. Maybe Vega could allow you to use that aggregation until it's implemented in the rest of Kibana. I'll leave this here, maybe somebody else has more ideas, but I doubt it.