anchor.diff:              let subscription = fun evt world ->
                   let world =
                       if pred evt world then
  -                        let eventTrace = EventTrace.record "Stream" "filter" evt.Trace
  +                        let eventTrace = EventTrace.record "Stream" "filterPlus" evt.Trace
                           EventWorld.publish<'a, Participant, 'w> evt.Data subscriptionAddress eventTrace evt.Publisher world
                       else world
                   (Cascade, world)
  
positive.code:                 let world = EventWorld.addEventState stateKey state world
                  let world =
                      if tracked then
                          let eventTrace = EventTrace.record "Stream" "track4" evt.Trace
                          let eventData = transformer state
                          EventWorld.publish<'b, Participant, 'w> eventData subscriptionAddress eventTrace evt.Publisher world
                      else world
  
negative.code:                 let world = unsubscribe world
                  EventWorld.unsubscribe<'w> subscriptionKey world
              let subscription = fun evt world ->
                  let eventTrace = EventTrace.record "Stream" "mapPlus" evt.Trace
                  let world = EventWorld.publish<'b, Participant, 'w> (mapper evt world) subscriptionAddress eventTrace evt.Publisher world
                  (Cascade, world)
              let world = EventWorld.subscribe5<'a, Participant, 'w> subscriptionKey subscription eventAddress (world.GetNullParticipant ()) world
  