恢复UITextView的undoManager

Question

在我的应用程序中，我有一个继承自UITextView的类，我需要在屏幕上创建和销毁此视图的许多实例。所以我的问题 - 有没有办法保存（在销毁之前）然后恢复（创建之后）每个实例的撤销/重做堆栈？

// After creation should be restoring like this.
// (This doesn't work certainly as undoManager is a readonly property)
self.undoManager = storedUndoManager;