业务场景：
之前用CoreData做数据管理时用的NSPersistentContainer，现在想要做CloudKit数据备份需要用到NSPersistentCloudKitContainer，但两者做衔接时遇到了问题：操作数据总发生崩溃和数据无法保存
错误特征：
Thread 1: Fatal error: 不能保存：Error Domain=NSCocoaErrorDomain Code=513 "未能存储该文件，因为你没有权限。" UserInfo={NSPersistentStoreOptions={ NSInferMappingModelAutomaticallyOption = 1; NSMigratePersistentStoresAutomaticallyOption = 1; }, reason=File is in Read Only mode due to Persistent History being detected but NSPersistentHistoryTrackingKey was not included., storeURL=
解决方案：
一旦启用了iCloud同步的NSPersistentCloudKitContainer，想再切换到NSPersistentContainer做数据操作，必须开启NSPersistentHistoryTrackingKey。
struct LocalPersistentContainer {
static** var shared: NSPersistentContainer = {
let container = NSPersistentContainer(name: "NoteData")
// 重点在于这两句
let description = container.persistentStoreDescriptions.first
description?.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
// 无需重新赋值给container即可生效
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
print("Unresolved error \(error), \(error.userInfo)")
}
})
**return** container
}()
}
