SKScene FPS与Xamarin一起过渡

Question

SKScenes的问题。 我有两个SKScenes。两者都有一些静态节点。它们与不同的ViewControllers相关联。当我执行从Scene1到Scene2的转换（反过来）时，初始场景似乎被删除（.Dispose（）方法被调用，它似乎根据调试输出重绘）。但是在经过2-3次转换后，FPS逐渐从30降到10或更低（！）。似乎场景仍在记忆中。我该怎么做才能妥善处理场景？

public override void ViewWillLayoutSubviews ()
    {
        base.ViewWillLayoutSubviews ();
        var skView = (SKView)View;
        if (skView.Scene == null) {
            Console.WriteLine ("Scene is to be created");
            skView.ShowsFPS = true;
            skView.ShowsNodeCount = true;

            // Create and configure the scene.
            var scene = new MatchmakingView (skView.Bounds.Size);

            scene.ScaleMode = SKSceneScaleMode.AspectFill;

            // Present the scene.
            skView.PresentScene (scene);

            scene.OnToWaiting += _OnToWaiting;
            scene.OnToMain += _OnToMain;
        }

    }

public override void ViewDidDisappear (bool animated)
    {
        base.ViewDidDisappear (animated);
        var skView = (SKView)View;
        var scene = (MatchmakingView)skView.Scene;
        scene.OnToWaiting -= _OnToWaiting;
        scene.OnToMain -= _OnToMain;
        skView.RemoveFromSuperview ();
        scene.Dispose ();
        skView.Dispose ();
        Console.WriteLine ("MMa removed");
    }