Feature Request: optimized counter?

For my application i needed a way to track (up to some maximum) the number of likes for each of a number of given post IDs, and I'm already tracking sets of likes on posts by user using roaring bitmaps here, So I implemented a thing thats a fixed size stack of bitmaps that lets me compactly store counts by post ID.

To do the adding, I have a loop that takes in the new bitmap to add in, and then does a series of Xor and AndNot calls to do the 'Add' (see here: https://github.com/whyrusleeping/fancycounter/blob/main/fancycounter.go#L95-L100 )

I'm wondering if theres an optimized way we could do this in a single call (instead of an Xor and an AndNot separately)

Thanks in advance, and thank you so much for this library in the first place!

Start with fancycounter.go lines 95-100, which are linked in the issue, and trace the Xor and AndNot operations used to add a bitmap. Then inspect the roaring bitmap API for related combined operations and determine whether the requested behavior can be supported as one call. Done means establishing whether an optimized operation is feasible and defining the needed library change.