Is there a property that can be used to recognize calendars across devices?
According to the Apple docs, the "calendarIdentifier" property cannot be used:
A full sync with the calendar will lose this identifier. You should have a plan for dealing with a calendar whose identifier is no longer fetch-able by caching its other properties.
I'm looking for something similar to EKEvent.calendarItemExternalIdentifier, which is the same and unique across devices, but for Calendars.