```
       
class CoreDataStack {
   
  // MARK: Properties
  private let modelName: String = "Model"
   
  var mainContext: NSManagedObjectContext {
    return self.storeContainer.viewContext
  }
   
   
  let storeContainer: NSPersistentCloudKitContainer
   
   
  init(){
    self.storeContainer = NSPersistentCloudKitContainer(name: self.modelName)
     
    guard let description = self.storeContainer.persistentStoreDescriptions.first else {
      fatalError("###\(#function): Failed to retrieve a persistent store description.")
    }
    //turn off일때 켜기
//    description.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
    description.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey)
     
    self.setiCloudSync()
     
    self.storeContainer.loadPersistentStores { (storeDescription, error) in
      if let error = error as NSError? {
        fatalError("Unresolved error \(error), \(error.userInfo)")
      }
    }
     
    // MARK: Only for First time in debug
//    self.schemaInitiation()
     
    let context = self.storeContainer.viewContext
    context.mergePolicy = NSMergeByPropertyStoreTrumpMergePolicy
    context.automaticallyMergesChangesFromParent = true
  }
   
   
  func setiCloudSync() {
    let iCloudSyncOn = UserDefaults.standard.bool(forKey: "iCloudSyncOn")
     
    guard let description = self.storeContainer.persistentStoreDescriptions.first else {
      fatalError("###\(#function): Failed to retrieve a persistent store description.")
    }
     
    if iCloudSyncOn {
      let id = "iCloud.hanung.test"
      description.cloudKitContainerOptions = NSPersistentCloudKitContainerOptions(containerIdentifier: id)
       
//      if !UserDefaults.standard.bool(forKey: "didBatchUpdateForForceSync") {
//        self.forceSyncAll()
//      }
    } else {
      description.cloudKitContainerOptions = nil
    }
  }
```