Alamofire.Manager class Scheduler { let backgroundWorkScheduler: ImmediateScheduler let mainScheduler: SerialDispatchQueueScheduler init() { let operationQueue = NSOperationQueue() operationQueue.maxConcurrentOperationCount = MangaContext.MAX_CONCURRENT_OPERATION_COUNT operationQueue.qualityOfService = NSQualityOfService.UserInitiated backgroundWorkScheduler = OperationQueueScheduler(operationQue