Migrate to C#12

Core/RenderManager.cs

@@ -792,7 +792,7 @@ internal class RenderManager : MonoBehaviour
         // removes frames, and it signals FrameDequeuedEvent for each one. The wait has a timeout so that the loop
         // re-checks the render thread state and pumps pending readback completions (see ThrottleWaitMilliseconds).
         isThrottling = false;
-        var frameLimit = QueueFrameLimit = ComputeQueueFrameLimit(texture!);
+        var frameLimit = QueueFrameLimit = ComputeQueueFrameLimit(texture);
 
         while (Instance.stage >= RenderStage.Render)
         {