anchor.diff:                          writer.RemoveRef range |> ignore
                   }
               )
  +            if isNew then
  +                transact (fun () -> x.MarkOutdated ())
  +            res
   
           member x.Set(range : Range1l, value : byte[]) =
               let count = range.Size + 1L
  
positive.code:             store.Resize 0n
  
          member x.Add(range : Range1l, view : BufferView) =
              lock x (fun () ->
                  let count = range.Size + 1L
  
                  let writer = 
                      bufferWriters.GetOrCreate(view, fun view ->
                          let remove w =
                              x.Dirty.Remove w |> ignore
                              bufferWriters.Remove view |> ignore
  
negative.code:                     let min = nativeint(range.Min + count) * asize
                      if store.Capacity < min then
                          store.Resize(Fun.NextPowerOfTwo(int64 min) |> nativeint)
         
                      lock writer (fun () -> 
                          if not writer.OutOfDate then
                              writer.Write(range)
                      )
  
  