 - Render system threading:
   - Make a list of thread-safe RenderSystem classes
    - For example HighLevelGpuProgram is thread safe but GpuProgram itself isn't
    - Classes that are safe to use outside of the render thread: RenderSystem, Mesh, Texture, HighLevelGpuProgram, Material, Shader, Technique
	- Classes that are only accessible from the render thread: GpuProgram, HardwarePixelBuffer, HardwareVertexBuffer, HardwareIndexBuffer
  - Make sure the user knows resources are shared between contexts. All resource updates are executed 
     before rendering a frame, so whichever context updated the resource last, was the version that will be used.