Lock _sid_to_service during event subscription
Lock _sid_to_service during event subscription

This makes sure that we know how to handle initial events that can appear
very quickly.

KennethNielsen/SoCo,dajobe/SoCo,dajobe/SoCo,petteraas/SoCo,SoCo/SoCo,SoCo/SoCo,petteraas/SoCo,KennethNielsen/SoCo,petteraas/SoCo