How to avoid duplicate posts in pagination?

Question

API

Hello!
I undertook to write my own API and look at the VKontakte API as an example. But I noticed such nonsense. In order to get the first group (page) of 10 posts, you need to run a query with parameters count=10&offset=0 .
All is well, but suppose while the user was reading these 10 posts, someone added 5 more posts. It turns out that when I receive the second group of posts with parameters count=10&offset=10 , I will get posts from 5 to 10 of the first request again. Because the offset value for posts has shifted due to 5 new ones.
How is this problem solved by VKontakte? After all, they do not have additional parameters such as the anchor of the first or last post.