anchor.diff:    Series<'K,'V>() as this =
       inherit Series()
       
  -    let c = new ThreadLocal<_>(Func<_>(this.GetCursor), true) 
  +    let c = Lazy(this.GetCursor) //new ThreadLocal<_>(Func<_>(this.GetCursor), true) 
   
       [<NonSerializedAttribute>]
       [<DefaultValueAttribute>]
  
positive.code:             )
            ) |> ignore
            { 
              new Object() with
                member x.Finalize() = (x :?> IDisposable).Dispose()
              interface IDisposable with
                member x.Dispose() = cts.Cancel();cts.Dispose();
            }
        finally
  
negative.code:             yield c.CurrentValue
          }
  
  //    override x.Finalize() =
  //      try
  //        for v in c.Values do
  //          try
  //            v.Dispose()
  //          with
  //          | :? ObjectDisposedException -> ()
  //        c.Dispose()
  //      with
  //      | :? ObjectDisposedException -> ()
        
  
      interface IEnumerable<KeyValuePair<'K, 'V>> with
  