Visualise length of event instead of a single timestamp

Is it possible to visualise a single event over a period of time by using one of its metrics?

The event has a timespan value, or it could have start/stop values, is it possible to display a block on the graph which starts at starttime and continues with a constant value until endtime?

The only approach I can think of is to copy the event for every second I want to create this block for, which would require preprocessing and consume a lot of extra disk space.

My data is in Elasticsearch but I could use another TSDB if one has this feature.