Describes order of calls to mixin methods (message impl) if two mixins implement the same message. If the same message on 2 mixins in 'move' in: 'class QuickBird extends Bird with FlutterMixin, SailMixin {}', the SailMixin.move (the rightmost) is called.

Also describes 1) a edge scenario where class is used as mixin, then it should define a factory constructor and be abstract. 2) if the same message on 2 mixins is 'move' the 'move' on the rightmost mixin is called (and no other mixin's 'move', unless the rightmost 'move' calls 'super'.

implements vs extends in Dart classes and mixins