Ensure room isn't deleted before leave presences are sent
This issue was introduced as part of the FMUC code that went in 4.6.0-beta. As of yet, this code is not released (other than in a beta).
When the last occupant leaves a room, the broadcast of the corresponding 'leave' presence is performed asynchronously. Smack integration tests regularly fail with this error:
It appears that the room is deleted from memory, before the presences have been properly sent.