 
     override func stopLoading()
         { }
-
-    static func synchronized<T>(_ action: () -> T) -> T
-        {
-        objc_sync_enter(NetworkStub.self)
-        defer { objc_sync_exit(NetworkStub.self) }
-        return action()
-        }
     }
 
 struct RequestStub

        return stub
        }

    static func add(_ stub: RequestStub)
        {
        synchronized
            { stubs.insert(stub, at: 0) }
        }

    static func clearAll()
        {
        Self.requestInitialization.await
            {
            synchronized { stubs = [] }
            }
        }

    override class func canInit(with request: URLRequest) -> Bool


    override func startLoading()
        {
        let stub = URLProtocol.property(forKey: Self.stubPropertyKey, in: request) as! RequestStub
        stub.awaitPermissionToGo()

        if SiestaSpec.envFlag("RandomTimeDelayInNetworkStubs")
