As the provider lists them (Google includes the organizer, Graph does not).
The provider's ID for the event in this calendar. Differs between attendees' calendars.
The iCalendar UID: the same in every attendee's calendar, so it is what other calendars match on.
The recurring series this occurrence belongs to, when it is one.
Null when the provider sent a time that does not determine an instant. Never a guess.
One event as a provider reports it. Lossy by design, like
GetEventsEvent.