anchor.diff:  
       /// Get or add a StepCounter
       static member StepCounter(name : string, step) =
  -        let monitorKey = OkanshiMonitor.GetMonitorKey(name, typeof<StepCounter>)
  +        let monitorKey = OkanshiMonitor.GetMonitorKey(name, typeof<StepCounter>, [||])
           let factory = fun () -> (new StepCounter(MonitorConfig.Build(name).WithTags(OkanshiMonitor.DefaultTags), step) :> IMonitor)
           monitorAgent.PostAndReply(fun reply -> GetMonitor(monitorKey, factory, reply)) :?> StepCounter
   
  
positive.code: open System.Collections.Concurrent
  
  /// Tuple representing a key used to identify a monitor
  type MonitorKey = (string * Type)
  /// Type representing a monitor factory
  type MonitorFactory = unit -> IMonitor
  
  
negative.code: 
      /// Get or add a PeakRateCounter
      static member PeakRateCounter(name : string, step) =
          let monitorKey = OkanshiMonitor.GetMonitorKey(name, typeof<PeakRateCounter>, [||])
          let factory = fun () -> (new PeakRateCounter(MonitorConfig.Build(name).WithTags(OkanshiMonitor.DefaultTags), step) :> IMonitor)
          monitorAgent.PostAndReply(fun reply -> GetMonitor(monitorKey, factory, reply)) :?> PeakRateCounter
  
  