anchor.diff:                                      match rj.InstanceAttributes.TryGetAttribute (v.semantic |> Symbol.Create) with
                                           | Some value ->
                                               let dep = x.CreateBuffer(value.Buffer)
  -                                            let view = createView (AttributeFrequency.PerInstances 1) value dep
  +                                            let view,d = createView (AttributeFrequency.PerInstances 1) value dep
  +                                            createdViews.Add d
                                               (v.attributeIndex, (dep, view, value.Buffer))
                                           | _ -> 
                                               failwithf "could not get attribute %A" v.semantic
  
positive.code:                 IndexBuffer = None
                  VertexArray = Unchecked.defaultof<_>
                  VertexAttributeValues = Map.empty
              }
  
      type PreparedRenderObject with
  
negative.code:                     match rj.VertexAttributes.TryGetAttribute (v.semantic |> Symbol.Create) with
                          | Some value ->
                              let dep = x.CreateBuffer(value.Buffer)
                              let view,d = createView AttributeFrequency.PerVertex value dep
                              createdViews.Add d
                              (v.attributeIndex, (dep, view, value.Buffer))
                          | _  -> 
                              match rj.InstanceAttributes with
  