我对NSManagedObjectContext的类型有一些疑问.让我们看一下苹果关于NSConfinementConcurrencyType的文档：
Confinement (NSConfinementConcurrencyType)
For backwards compatibility,this is the default. You promise that context will not be used by any thread other than the one on which you created it. In general,to make the behavior explicit you’re encouraged to use one of the other types instead.
You can only use this concurrency type if the managed object context’s parent store is a persistent store coordinator.
我无法理解为什么这种类型只能由父存储是持久存储协调器的对象上下文使用.例如,我创建一个NSManagedObjectContext使用这种类型,并将它的父存储设置为另一个上下文,是否会产生一些错误.
