descends property
Descends is the published value the working model grew out of: the newest one whose mass count it has reached or passed. Empty when nothing has been published yet. It is DERIVED from the count and never stored, so an instant rollback is right for free — adopting an older value moves the count backward and this answers with that older value, where a stored pointer would be a second fact to keep in step. Read with Learned it is also the DRIFT: this model is Descends plus however many events the two counts differ by.
Please note: This property should have been non-nullable! Since the specification file does not include a default value (using the "default:" property), however, the generated source code must fall back to having a nullable type. Consider adding a "default:" property in the specification file to hide this note.
Implementation
String? descends;