Hi, this is just a conceptual question. I've got a use case basically being OLAP computations on large datasets, something Druid is great at. However, in this specific case to get the right kind of hardware cost efficiency for live queries we would need to have a custom segment format, and do a bit more complex computations when scanning them than what Druid normally allows. As far as I understand, segment format is not pluggable with plugins. I like a lot the segment management part of Druid though, and the model of historicals vs. brokers for large-scale compute. And so I wonder, how difficult would be to hack code of Druid historicals to support a custom format?