anchor.diff:  open System.IO
   open System.Numerics
   open System.Runtime.InteropServices
  +open System.Text
   open System.Threading
   open System.Threading.Tasks
   open SDL2
  
positive.code:         let message = { Elevation = Single.MaxValue; AssetTag = AssetTag.generalize image; Horizon = 0.0f; RenderDescriptor = SpritesDescriptor { Sprites = sprites }}
          renderer.RenderLayeredMessages.Add message
  
      /// Make a Renderer.
      static member make window =
  
  
negative.code:         | SglWindow window -> OpenGL.Hl.CreateSgl410Context window.SglWindow |> ignore<nativeint>
          | WfglWindow _ -> () // TODO: 3D: see if we can make current the GL context here so that threaded OpenGL works in Gaia.
          OpenGL.Hl.Assert ()
  
          OpenGL.Gl.DebugMessageCallback (GlRenderer2d.GLDebugProc, nativeint 0)
  
          // create one-off sprite and text resources
          let spriteShader = OpenGL.Hl.CreateSpriteShader ()
  