anchor.diff:                  then None
                   else
                       let x = inbox.[0]
  -                    inbox.RemoveAt(0)
  +                    inbox.RemoveAt(0);
                       Some(x)
   
           member x.Post(msg) =
  
positive.code:         let ensurePulse() = 
              match pulse with 
              | null -> 
                  pulse <- new AutoResetEvent(false)
              | _ -> 
                  ()
              pulse
  
negative.code:                 | None -> 
                      match pulse with 
                      | null -> 
                          () // no one waiting, leaving the message in the queue is sufficient
                      | ev -> 
                          // someone is waiting on the wait handle
                          ev.Set() |> ignore
  
                  | Some(action,trampolineHolder) -> 
  