* FIX: ensures stream update object is scoped to its initial topic
Before this commit you could end up in this situation where a `post-updater` is constructed for a specific topic, but the user changes topic mid steam and it ends up updating the same post number but in a different topic as we were only checking for `post_number` and not the combination of `topic_id` + `post_number`.
* we should have the topic
Joffrey JAFFEUX
b817810d46