anchor.diff:                                              pauseBeforeBackgroundWork
                                       return! inbox.TryReceive(timeout) }
   
  -                    let currentThread = Thread.CurrentThread
  -                    currentThread.CurrentUICulture <- culture
  +                    use _disposable = useThread Thread.CurrentThread
   
                       match msg with
                       | Some (SetBackgroundOp bgOpOpt) -> 
  
positive.code:     let mutable bgOpCts = new CancellationTokenSource()
  
      let threadsUsed = System.Collections.Concurrent.ConcurrentDictionary<int, byte>()
  
      /// Mailbox dispatch function.
      let builder = 
  
negative.code:                         Trace.TraceInformation("Reactor: {0:n3} --> {1}.{2} ({3}), remaining {4}", DateTime.Now.TimeOfDay.TotalSeconds, userOpName, opName, opArg, inbox.CurrentQueueLength)
                          let time = Stopwatch()
                          time.Start()
                          op ctok
                          time.Stop()
                          let span = time.Elapsed
                          //if span.TotalMilliseconds > 100.0 then 
  