Custom aggregate functions for groups in tables

Sorry if this was posted somewhere else, please direct me to it if that’s so , so I’ll upvote it and delete this one.

I thought a lot about what should be my first feature request (most are already written by you guys) , so there it is …

Ability to write custom group aggregate functions !

The existing ones are super fast, so there are definitely some smart algorithms behind them , but there are too few (count,sum,simple average,…) .

In my case, tens of times I needed basic moving averages, and I used the VCs tactics, but of course with performance downsides.

If it was possible, I would have combined two of the existing group agregate functions, two sums most of the times.

I think this can impact in a positive way (many of our slices,VCs and so on could be eliminated), making it possible to redisign many apps , gaining performance improvement.

What do you think ?