 @objcMembers public class MXBackgroundSyncService: NSObject {
     
     private enum Queues {
-        static let processingQueue: DispatchQueue = DispatchQueue(label: "MXBackgroundSyncServiceQueue")
         static let dispatchQueue: DispatchQueue = .main
     }
     

                
                if let event = self.syncResponseStore.event(withEventId: eventId, inRoom: roomId), !self.canDecryptEvent(event) {
                    //  we got the event but not the keys to decrypt it. continue to sync
                    Queues.processingQueue.async {
                        self.launchBackgroundSync(forEventId: eventId, roomId: roomId, completion: completion)
                    }
                } else {
                    //  do not allow to sync anymore
                    Queues.processingQueue.async {
                        self._event(withEventId: eventId, inRoom: roomId, allowSync: false, completion: completion)
                    }
                }
            case .failure(let error):
                guard let _ = self else {

        static let syncRequestPresence: String = "offline"
    }
    
    private let processingQueue: DispatchQueue
    private let credentials: MXCredentials
    private let syncResponseStore: MXSyncResponseStore
    private let store: MXStore
