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

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

    public func event(withEventId eventId: String,
                      inRoom roomId: String,
                      completion: @escaping (MXResponse<MXEvent>) -> Void) {
        processingQueue.async {
            self._event(withEventId: eventId, inRoom: roomId, completion: completion)
        }
    }
