anchor.diff:      ///     Sends a kill signal to the worker process.
       /// </summary>
       /// <param name="signal">Process exit signal. Defaults to 1.</param>
  -    member __.Kill(?signal : int) : unit = 
  +    member __.Kill([<O;D(null:obj)>]?signal : int) : unit = 
           let signal = defaultArg signal 1
           protect(fun () -> aref <-- Kill signal)
   
  
positive.code:     /// <param name="runAsBackground">Run as background process. Defaults to false.</param>
      /// <param name="heartbeatInterval">Specifies the default heartbeat interval emitted by the worker. Defaults to 500ms</param>
      /// <param name="heartbeatThreshold">Specifies the maximum time threshold of heartbeats after which the worker will be declared dead. Defaults to 10sec.</param>
      static member SpawnAsync (?hostname : string, ?port : int, ?workingDirectory : string, ?maxConcurrentWorkItems : int,
                                      ?logLevel : LogLevel, ?logFiles : seq<string>, ?useAppDomainIsolation : bool, ?runAsBackground : bool,
                                      ?heartbeatInterval : TimeSpan, ?heartbeatThreshold : TimeSpan) =
          async {
              let exe = ThespianWorker.LocalExecutable
              let logFiles = match logFiles with None -> [] | Some ls -> Seq.toList ls
  
negative.code:         | Some(_,state) -> Some state
  
      /// Initializes worker instance as master node in new cluster state.
      member internal __.InitAsClusterMasterNode(storeConfig : ICloudFileStore, [<O;D(null:obj)>]?miscResources : ResourceRegistry) = async {
          return! protectAsync (aref <!- fun ch -> InitMasterNode(storeConfig, miscResources, ch))
      }
  
  