alright so I thought about this thing for a while but I think I got the Gist of it haha
Efficient syncing for huge lists, accounting for new items, changes and deletions.
Connection basis is between server and clients, one-to-many. Might be most efficient in websocket format, because of all the back-and-forth.
I find that the most difficult part of this problem is determining what the source of truth is, because the clients can request a sync at literally any time.