anchor.diff:                          store.Resize(Fun.NextPowerOfTwo(int64 min) |> nativeint)
                               
                       lock writer (fun () -> 
  -                        if writer.OutOfDate then
  +                        if not writer.OutOfDate then
                               writer.Write(range)
                       )
  +
   
   
                           
  
positive.code:                         writer.RemoveRef range |> ignore
                  }
              )
  
          member x.Add(index : int, data : IMod) =
              lock x (fun () ->
                  let mutable isNew = false
                  let writer =
                      uniformWriters.GetOrCreate(data, fun data ->
                          isNew <- true
  
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)
                      )
  
  