     }
 
     public func performInBackground(tasks: [ContextClosure], completion: (() -> ())? = nil) {
-        Logging.log("Perform \(tasks.count) tasks")
+        Logging.log("Perform \(tasks.count) tasks on \(stack.identifier)")
         if let task = tasks.first {
             stack.performUsingWorker() {
                 context in

        return container.viewContext
    }
    fileprivate var managedObjectModel: NSManagedObjectModel!
    
    private var workerCount = 0
    

    private var wipeDatabaseOnConflict = false
    private var pathToSQLiteFile: URL?
    private let mergePolicy: NSMergePolicyType
    fileprivate let identifier: String
    
    private static var spawnedBackgroundCount = 0
    
