private void RemoveGraphics(OpenGLWindowGraphics graphics)
 {
     lock (_graphics)
     {
         _graphics.Remove(graphics);
     }
 }
        public GraphicsContext CreateGraphics(Window window, bool vsync)
        {
            var graphics = new OpenGLWindowGraphics(this, window, vsync);

            lock (_graphics) { _graphics.Add(graphics); }
            return(graphics);
        }