anchor.diff:          var
   
       static member Create() =
  -        let mutable var = JavaScript.JS.Undefined
  +        let mutable var = jsNull()
           var <-
               {
                   Const = false
  
positive.code: 
      [<MethodImpl(MethodImplOptions.NoInlining)>]
      static member Create v =
          let mutable var = JavaScript.JS.Undefined
          var <-
              {
                  Const = false
  
negative.code: 
      static member Set var value =
          if var.Const then
              printfn "WebSharper UI.Next: invalid attempt to change value of a Var after calling SetFinal"
          else
              Snap.MarkObsolete var.Snap
              var.Current <- value
  