pub fn begin(
questions: &Questions,
talks: &Talks,
q: &Question,
talk: &Talk,
) -> Result<bool>Expand description
Record the hand-over and queue the question as the chat’s next message.
Returns false (and changes nothing) when the question was already handed
over. The question is not otherwise touched: still Open, no thread turn.
When queueing fails the record is withdrawn, so the owner can try again.