The first message(s) received in a 1:1 conversation is lost about jabbercat

[horazont]

Also affects non-MUC 1:1 conversations.

I wonder if this is related to the occasional non-visibility of history in MUCs, in which case it would be a race-condition inside jclib/jabbercat.

[horazont]

The race-condition is in jabbercat. The following happens:

1. A message is received and a "spontaneous" p2p conversation is created, emitting a bunch of creation events.
2. In those events, the conversation and its view is set up properly. The QWebEngineView is created.
3. The event handlers return to the p2p handler, which in turn emits on_message for the message which was received.
4. The on_message event is received by the view, but ignored because the web view has not finished initialising yet.
5. The web view is ready, messages can now be added normally.

This will be fixed with #26.

(This does not affect MUCs or locally initiated conversations because the Web Engine usually has enough time to initialise before the first message arrives.)