Whether this is a shortened version of update, not containing the poll itself.
The poll.
When isShort is set, mtcute creates a stub poll
with empty question, answers and flags
(like quiz, public, etc.)
If you need access to them, you should map the pollId with full poll on your side (e.g. in a database) and fetch from there.
Bot API and TDLib do basically the same internally, and thus are able to always provide them, but mtcute currently does not have a way to do that.
Poll state has changed (stopped, somebody has voted in an anonymous poll, etc.)
Bots only receive updates about polls which were sent by this bot