EventStreamRecord

The events one command produced, committed together by one append: the unit of fact (documentation/designs/08-data-protocols.md §4).

• version is the aggregate's version after this stream; the first stream of an aggregate is version 1 and each next one is exactly one more.

• commandType is the model's name of the command that produced it (context.aggregate.Command, not a class name): a request id reused by a command of another type is told apart from a retry by it.

• scope is the aggregate's owner and space after this commit, not the caller's: every fact carries it, so projections and query authorization read it without replaying history.

• causation and headers come from the command: the chain it belongs to and the request facts admission kept.

• operator comes from the command too: whose name the commit is recorded in, the primary record of an audit; null for an anonymous caller.

• access are the aggregate's access attributes, the built-in owner and space among them, in their stored form (me.ahoo.wow.spi.access.AccessValues): those after this commit when it is appended, and then always the aggregate's current ones, which a stamp writes over its earlier streams when they change, so the events model authorizes a timeline by what the aggregate is now. Null when not stamped: a stream appended before the log recorded them, or imported without them, until a stamp gives them. accessVersion is the version they are of: the stream's own when appended with them (the default when access is given), the stamp's after a stamp, null with access. A writer of a copy of them keeps the one of the later version, which values cannot tell.

• The schedules a decision set or cancelled are among its events, as the system events wow.ScheduleSet and wow.ScheduleCancelled, from which the built-in timers subscription derives the timer store.

• rejection is the rejection whose events this stream holds, when a decision rejected its command with events, from the headers under REJECTION_PREFIX (wow.rejection.code, .message, .extensions); null for a commit. Its events are ordinary events of the aggregate, which projections and sagas handle as any; a retry of the command is answered with the same rejection.

Fields may be added: construct one with of; the constructor is internal to Wow.