Efficiency of replicated structs

I understand that UE is smart enough not to replicate unchanged single variables, but what about structs that contain multiple variables. If my struct contains an X integer and a Y integer, and I change the Y, will the entire struct be marked as dirty or will just the Y get replicated?

Kinda old question, but still no answer. Unfortunately I didn’t find much info on this subject either (besides this question). :frowning:
Could someone from Epic answer here or under given url? Would be really good to know how exactly does that replication works for structs.