Discussed during HL7 Connectathon with Isaac, Bas, and Will.   Agreed that subscribers should subscribe to a syncerror event because not all systems will care or know how to handle them, so we shouldn't automatically send out sync error events. Only send them to those apps that care and have subscribed.   We will also clarify that the subscriber can send a syncerror notification to the hub, just like a normal Request for Context Change, to inform the hub that they were unable to change context. This is to handle the cases where a subscriber cannot synchronously change their context in response to an event notification so the HTTP response will just represent receiving the notification, not acknowedgement of actually changing context.