I'm connecting to an IMAP server that boots IDLE connections after 30 minutes. I'm using imap-3.0.0-alpha.14, pretty much straight forward

    let imap = client.login(username, password)?;
    let mbox = imap.select(inbox)?;
    imap.idle().wait_while(|response| { ... });

I works well, apart from getting booted periodically.

I believe the issue may be, that the time is not counted from the start of the IDLE loop, but for every read, since the timeout is implemented by calling TcpStream::set_read_timeout() once before the loop. So when a response arrives on the client, the timeout is effectively reset.