Following along with WWDC17 Session 210 - What's new in Core Data:I ticked a couple of string properties on an Entitiy in Core Data UI modeler - Index in Spotlightthen with the instantiated NSManagedObjectModel set an expression to the entity coreSpotlightDisplayNameExpression:if let myEntity = mom.entitiesByName["MyEntity"] { myEntity.coreSpotlightDisplayNameExpression = NSExpression(block: { (object, expressions, dict) -> Any in let displayName = CSLocalizedString(localizedStrings: ["en": "My Item"]) return displayName.localizedString() } }(Don't know if this NSExpression works at all as block not been called as of yet)then subclassed NSCoreDataCoreSpotlightDelegateclass MyCoreDataCoreSpotlightDelegate: NSCoreDataCoreSpotlightDelegate { override func attributeSet(for object: NSManagedObject) -> CSSearchableItemAttributeSet? { guard let attributeSet = super.attributeSet(for: object) else { return nil } if "MyEntity" == object.entity.name { let item = object as! MyEntity attributeSet.displayName = item.itemName attributeSet.contentDescription = item.note } return attributeSet } }(Don't know if this override works at all as not been called as of yet)Setting up Core Data with NSPersistentContainer:let persistentStore = NSPersistentStoreDescription(url: dataStoreURL) persistentStore.setValue("WAL" as NSObject?, forPragmaNamed: "journal_mode") persistentStore.setOption(NSNumber(value: true), forKey:NSPersistentHistoryTrackingKey) let coreSpotlightDelegate = MyCoreDataCoreSpotlightDelegate(forStoreWith:persistentStore, model: persistentContainer.managedObjectModel) persistentStore.setOption(coreSpotlightDelegate, forKey:NSCoreDataCoreSpotlightExporter) persistentContainer.persistentStoreDescriptions = [persistentStore] persistentContainer.loadPersistentStores { storeDescription, error in }I have even added the Entitlement to talk to Core Spotlight 'com.apple.application-identifier = $(TeamIdentifierPrefix)$(CFBundleIdentifier)', just in case.....Unfortunately, this setup results in the main thread being blocked as soon as loadPersistentStores is called. Cpu runs at about 30-40% continuously, disk activity 1 MB/s, memory doesnt seem to increase at all.Pausing gives us a backtrace of:* thread #1, queue = 'NSManagedObjectContext 0x6040003c7530', stop reason = signal SIGSTOP * frame #0: 0x0000000116fe47fe libsystem_kernel.dylib`semaphore_wait_trap + 10 frame #1: 0x0000000116b598cf libdispatch.dylib`_dispatch_sema4_wait + 16 frame #2: 0x0000000116b5a018 libdispatch.dylib`_dispatch_semaphore_wait_slow + 101 frame #3: 0x00000001142d9aeb CoreData`-[NSCoreDataCoreSpotlightDelegate _updateSpotlightClientStateForHistoryTracking:] + 299 frame #4: 0x00000001142d8ea7 CoreData`__73-[NSCoreDataCoreSpotlightDelegate _importObjectsUpdatedSinceTransaction:]_block_invoke + 263 frame #5: 0x00000001140df748 CoreData`developerSubmittedBlockToNSManagedObjectContextPerform + 168 frame #6: 0x0000000116b5933d libdispatch.dylib`_dispatch_client_callout + 8 frame #7: 0x0000000116b60235 libdispatch.dylib`_dispatch_queue_barrier_sync_invoke_and_complete + 392 frame #8: 0x00000001140df64e CoreData`-[NSManagedObjectContext performBlockAndWait:] + 286 frame #9: 0x00000001142d8d3f CoreData`-[NSCoreDataCoreSpotlightDelegate _importObjectsUpdatedSinceTransaction:] + 287 frame #10: 0x00000001142da05a CoreData`-[NSCoreDataCoreSpotlightDelegate _catchUpToCurrentTransaction] + 218 frame #11: 0x000000011408a2d9 CoreData`-[NSPersistentStoreCoordinator addPersistentStoreWithType:configuration:URL:options:error:] + 969 frame #12: 0x0000000114199f50 CoreData`-[NSPersistentStoreCoordinator _doAddPersistentStoreWithDescription:privateCopy:completionHandler:] + 336 frame #13: 0x000000011419a361 CoreData`-[NSPersistentStoreCoordinator addPersistentStoreWithDescription:completionHandler:] + 177 frame #14: 0x000000011414ee7c CoreData`-[NSPersistentContainer loadPersistentStoresWithCompletionHandler:] + 668 frame #15: 0x000000010df48093 MyNewApp`SharedStoreHelper.init(storeName="0E4D1B65-58DB-464D-B64C-39D6C547F2F2", shareOwner="__defaultOwner__", coreSpotlightDelegateClass=MyNewApp.MyCoreDataCoreSpotlightDelegate, completion=0x000000010e06b360 MyNewApp`partial apply forwarder for closure #2 (Swift.Bool, MyNewApp.SharedStoreHelper) -> () in MyNewApp.ReloadStoresOperation.(reloadStores in _05B52F3B437462E7EAD7CB8BA8EFB1A6)(MyNewApp.SharedStoreHelper.Type, Swift.Optional<(Swift.Bool, Swift.Optional<MyNewApp.ArrayChanges>) -> ()>) -> () at ReloadStoresOperation.swift) at SharedStoreHelper.swift:101 frame #16: 0x000000010e0b708d MyNewApp`MyNewAppSharedStoreDataManager.init(storeName="0E4D1B65-58DB-464D-B64C-39D6C547F2F2", shareOwner="__defaultOwner__", coreSpotlightDelegateClass=MyNewApp.MyCoreDataCoreSpotlightDelegate, completion=0x000000010e06b360 MyNewApp`partial apply forwarder for closure #2 (Swift.Bool, MyNewApp.SharedStoreHelper) -> () in MyNewApp.ReloadStoresOperation.(reloadStores in _05B52F3B437462E7EAD7CB8BA8EFB1A6)(MyNewApp.SharedStoreHelper.Type, Swift.Optional<(Swift.Bool, Swift.Optional<MyNewApp.ArrayChanges>) -> ()>) -> () at ReloadStoresOperation.swift) at MyNewAppSharedStoreDataManager.swift:0 frame #17: 0x000000010e0b6df1 MyNewApp`MyNewAppSharedStoreDataManager.__allocating_init(storeName:shareOwner:coreSpotlightDelegateClass:completion:) at MyNewAppSharedStoreDataManager.swift:0 frame #18: 0x000000010e06802b MyNewApp`ReloadStoresOperation.reloadStores(storeType=MyNewApp.MyNewAppSharedStoreDataManager, completionHandler=0x000000010defda10 MyNewApp`partial apply forwarder for closure #1 (Swift.Bool, Swift.Optional<MyNewApp.ArrayChanges>) -> () in closure #1 (__ObjC.NSPersistentStoreDescription, Swift.Optional<Swift.Error>) -> () in MyNewApp.MultiStoreManager.init(MyNewApp.SharedStoreHelper.Type, coreSpotlightDelegateClass: Swift.Optional<__ObjC.NSCoreDataCoreSpotlightDelegate.Type>, (Swift.Bool, MyNewApp.MultiStoreManager) -> ()) -> MyNewApp.MultiStoreManager at MultiStoreManager.swift, self=0x0000600000675140) at ReloadStoresOperation.swift:49 frame #19: 0x000000010e0673f3 MyNewApp`ReloadStoresOperation.beginAsynchronousTask(self=0x0000600000675140) at ReloadStoresOperation.swift:24 frame #20: 0x000000010e067424 MyNewApp`@objc ReloadStoresOperation.beginAsynchronousTask() at ReloadStoresOperation.swift:0 frame #21: 0x0000000112a85ee8 Ensembles`-[CDEAsynchronousOperation start](self=0x0000600000675140, _cmd="start") at CDEAsynchronousOperation.m:50 frame #22: 0x0000000112bb91e8 Foundation`__NSThreadPerformPerform + 334 frame #23: 0x0000000114669101 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17 frame #24: 0x0000000114708f71 CoreFoundation`__CFRunLoopDoSource0 + 81 frame #25: 0x000000011464da6b CoreFoundation`__CFRunLoopDoSources0 + 267 frame #26: 0x000000011464cfff CoreFoundation`__CFRunLoopRun + 1279 frame #27: 0x000000011464c889 CoreFoundation`CFRunLoopRunSpecific + 409 frame #28: 0x00000001187539c6 GraphicsServices`GSEventRunModal + 62 frame #29: 0x000000011060c5d6 UIKit`UIApplicationMain + 159 frame #30: 0x000000010e07ee27 MyNewApp`main at AppDelegate.swift:18 frame #31: 0x0000000116bd5d81 libdyld.dylib`start + 1There is almost zero information about how to set this up (apple documentation or Stackoverflow etc.), other than the WWDC17 210 session. Does anyone have any ideas what to try next? or even if this is meant to work at all?Many thanks in advance