Wrongful IDLE timeout reset on response

[gin-ahirsch]

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.

[jonhoo]

Ah, I see, specifically the problem is if the callback doesn't terminate during the wait period, but instead just passively consumes the responses and "continues" the IDLE. Because in that case no signal is sent to the server to indicate that the client is still active. Thanks for the PR — will take a look! And sorry for the delay :)