anchor.diff:                                      ());
                           Cts = new CancellationTokenSource()  }
                   member self.Result = 
  -                    dict |> ofSeq |> map (fun keyValue -> (keyValue.Key, !keyValue.Value)) |> withDegreeOfParallelism !stream.DegreeOfParallelism }
  -
  -        let stream = if stream.PreserveOrdering then stream.Stream() |> Stream.toSeq |> ofSeq |> withDegreeOfParallelism !stream.DegreeOfParallelism else stream
  +                    dict |> ofSeq |> map (fun keyValue -> (keyValue.Key, !keyValue.Value)) |> withDegreeOfParallelism stream.DegreeOfParallelism }
  +
  +        let stream = if stream.PreserveOrdering then stream.Stream() |> Stream.toSeq |> ofSeq |> withDegreeOfParallelism stream.DegreeOfParallelism else stream
           stream.Apply collector
           
           
  
positive.code:         let results = new List<'State ref>()
          let collector = 
              { new Collector<'T, 'State> with
                  member self.Iterator() = 
                      let accRef = ref <| state ()
                      results.Add(accRef)
  
negative.code:             member self.Apply<'S> (collector : Collector<'R, 'S>) =
                  let collector = 
                      { new Collector<'T, 'S> with
                          member self.DegreeOfParallelism = collector.DegreeOfParallelism
                          member self.Iterator() =
                              let { Index = index; Func = iter } as iterator = collector.Iterator()
                              {   Index = iterator.Index; 
  