         sink event
     unsubAll = ->
       sub.unsub?() for sub in subscriptions
+      undefined
     subscribeInput = (subscription) ->
       subscription.unsub = (subscription.input.subscribeInternal(guardedSink(subscription.input)))
     unsubscribeInput = (input) ->

          spy(obs)
      finally
        delete registerObs.running

withMethodCallSupport = (wrapped) ->
  (f, args...) ->

  flush = ->
    while waiterObs.length > 0
      flushWaiters(0)
    undefined

  flushWaiters = (index) ->
    obs = waiterObs[index]
