Signed-off-by: Kurt Roeckx <kurt@roeckx.be>

The conversion between the two is now direct and thus shouldn't lose the state_keys.

Conduit did not send the event in /sync because of a race condition.
There is a brief moment in time where Conduit accepted the event, but
did not store it yet. So when the client /syncs it updates the since
token without sending the event. I hope I fixed it by significantly
shortening the race-condition period.