+ (when (update-thread *empire-session*)
+ (empire-log:info "~a: Killing update thread ~a." *empire-session* (update-thread *empire-session*))
+ (sb-thread:terminate-thread (update-thread *empire-session*)))
+ (setf (update-thread *empire-session*) sb-thread:*current-thread*)
+ (let ((next-update (locked-queue:dequeue (update-queue *empire-session*))))
+ (setf (update-thread *empire-session*) nil)
+ next-update)))