AngularDart示例中的Chapter_06 当我在Dartium中运行它时，有一些错误：
Observer reaction functions should not change model.
These watch changes were detected: ctrl.allRecipes: [Instance of 'Recipe', Instance of 'Recipe']
cmp.categories: [Appetizers, Salads, Soups, Main Dishes, Side Dishes, Desserts]
<= [Appetizers, Salads, Soups, Main Dishes, Side Dishes, Desserts]
These observe changes were detected:
STACKTRACE:
#0 RootScope.flush.<anonymous closure> (package:angular/core/scope.dart:554:11)
#1 RootScope.flush (package:angular/core/scope.dart:560:9)
#2 RootScope.flush (package:angular/core/scope.dart:561:7)
#3 RootScope.flush (package:angular/core/scope.dart:561:7)
#4 apply (package:angular/core/scope.dart:262:18)
#5 _rootRun (dart:async/zone.dart:710)
#6 _rootRun (dart:async/zone.dart:711)
#7 _rootRun (dart:async/zone.dart:711)
#8 _ZoneDelegate.run (dart:async/zone.dart:440)
#9 NgZone._finishTurn (package:angular/core/zone.dart:96:21)
如何解决？