Better cope with null callbacks.
Better cope with null callbacks.

weilitao/flambe,aduros/flambe,Disar/flambe,mikedotalmond/flambe,mikedotalmond/flambe,markknol/flambe,markknol/flambe,Disar/flambe,weilitao/flambe,playedonline/flambe,aduros/flambe,markknol/flambe,weilitao/flambe,aduros/flambe,playedonline/flambe,playedonline/flambe,aduros/flambe,Disar/flambe,mikedotalmond/flambe,playedonline/flambe,mikedotalmond/flambe,Disar/flambe,weilitao/flambe