anchor.diff:      let GITHUB_API = Plug.New(new XUri("https://api.github.com"))
       let DATE_PATTERN = "yyyyMMdd"
       let logger = LogManager.GetLogger typedefof<PullRequestService>
  +    let timerFactory = TaskTimerFactory.Create(self)
   
       // Supervisor agent
       let supervisor =
  
positive.code: 
      // Merge agent
      let mergeAgent =
          let timerFactory = self.TimerFactory
          let cache = new ExpiringDictionary<XUri, int>(timerFactory)
          cache.EntryExpired.Add <|
              fun args ->
                  let prUri, retry = args.Entry.Key, args.Entry.Value
  
negative.code:             let rec loop (cache : ExpiringDictionary<XUri, int>) = async {
                  let! msg = inbox.Receive()
                  cache.Set(msg, 0, mergeabilityTTL)
                  logger.DebugFormat("Queued '{0}' for mergeability check in '{1}'", msg, mergeTTL)
                  return! loop cache
              }
              loop(cache)
  