async fn fetch_idle(
connection: &mut Imap,
Implement a single iteration of IMAP loop.
This function performs all IMAP operations on a single folder, selecting it if necessary and
handling all the errors. In case of an error, it is logged, but not propagated upwards. If
critical operation fails such as fetching new messages fails, connection is reset via
trigger_reconnect, so a fresh one can be opened.