Ensure callbacks are called even if it was set already.
Ensure callbacks are called even if it was set already.

bsanders/kazoo,kormat/kazoo,jacksontj/kazoo,Asana/kazoo,jacksontj/kazoo,harlowja/kazoo,python-zk/kazoo,max0d41/kazoo,max0d41/kazoo,AlexanderplUs/kazoo,rockerbox/kazoo,kormat/kazoo,rgs1/kazoo,tempbottle/kazoo,harlowja/kazoo,rackerlabs/kazoo,pombredanne/kazoo,AlexanderplUs/kazoo,rackerlabs/kazoo,rgs1/kazoo,python-zk/kazoo,tempbottle/kazoo,pombredanne/kazoo,bsanders/kazoo,rockerbox/kazoo