OMEMO: Create new session automatically when client is over 2000 messages behind
In a multi-device setup, when one user's client (let's call it A) falls behind the other clients of that user for over 2000 messages, the session becomes invalidated. Consequently, client A does not receive the messages from the other clients anymore. This becomes visible in the logs like so:
18.08.2017 21:05:38 (W) gajim.plugin_system.omemo: No Session found No valid sessionsOver 2000 messages into the future!
18.08.2017 21:05:38 (W) gajim.plugin_system.omemo: sender_jid => zb@REDACTED sid =>1505163973
It would be desirable that a new session is created automatically at client A, when such a state is reached.