`format=tree` pagination provides top-level comments with all replies
and returns the last top-level comment as `last_comment` to be used
as `offset` for the next page. If comments and replies overflow
the limit, the one stepping out of the limit will not be returned.
If the first comment and its replies after the given offset overflow
the limit, it will be returned with all the replies.
`format=plain` pagination works by providing all comments and returning
the last comment as `last_comment` to be used as `offset`
for the next page.
Dmitry Verkhoturov
82a0888c42