anchor.diff:  
           let speedup = ot / nt
           Log.line "factor: %A" speedup
  -
   
   module Test =
   
  
positive.code:                                     cache.Remove i |> ignore
  
                                      if isDifferential then 
                                          dirty.Add n |> ignore
                                          dirty.Remove f |> ignore
                                      count <- count - 1
                                  | _ ->
  
negative.code:     let private jumpSize = 5n
      
      [<AllowNullLiteral>]
      type private Fragment<'a> =
          class
              val mutable prev : Fragment<'a>
              val mutable next : Fragment<'a>
  