changes property Null safety

Stream<List<C>> changes
override

Emits a list of changes when the state of the object changes.

Changes should produced in order, if significant.

Implementation

@override
Stream<List<C>> get changes =>
    (_changes = StreamController<List<C>>.broadcast(
      sync: true,
      onListen: observed,
      onCancel: unobserved,
    ))
        .stream;