anchor.diff:          
   
               clear.Run(RenderToken.Empty, fbo)
  -            OpenTK.Graphics.OpenGL4.GL.Sync()
  +            GL.Sync()
               let token = RenderToken()
               task.Run(token, fbo)
  -            OpenTK.Graphics.OpenGL4.GL.Sync()
  +            GL.Sync()
               Log.line "%d objects" token.DrawCallCount
               let pi = runtime.Download(color, PixFormat.ByteRGBA)
               pi.SaveAsImage(@"C:\Aardwork\urdar.png")
  -            OpenTK.Graphics.OpenGL4.GL.Sync()
  +            GL.Sync()
               Log.line "starting update test"
               let mutable iterations = 0
               let sw = Stopwatch()
  
positive.code: open System
  open NUnit.Framework
  open FsUnit
  open Aardvark.Rendering.GL
  open Aardvark.Base
  open Aardvark.Base.Incremental
  
negative.code: 
  
          clear.Run(RenderToken.Empty, fbo) |> ignore
          GL.Sync()
          let token = RenderToken()
          task.Run(token, fbo)
          GL.Sync()
          Log.line "%d objects" token.DrawCallCount
          let pi = runtime.Download(color, PixFormat.ByteRGBA)
          pi.SaveAsImage(@"C:\Aardwork\gugu.png")
          GL.Sync()
          //task2.Run fbo |> ignore
          //OpenTK.Graphics.OpenGL4.GL.Sync()
  
  