             unsubscribeFromSource()
             Bacon.noMore
         else
-          queue = (queue or []).concat([event])
+          queue.push(event)
           Bacon.more
     @push = (event) =>
       UpdateBarrier.inTransaction event, this, pushIt, [event]

  constructor: (subscribe, handleEvent) ->
    subscribe ?= -> nop
    subscriptions = []
    queue = null
    pushing = false
    ended = false
    @hasSubscribers = -> subscriptions.length > 0

      else
        assertFunction sink
        subscription = { sink: sink }
        subscriptions.push(subscription)
        if subscriptions.length == 1
          unsubSrc = subscribe @handleEvent
          unsubscribeFromSource = ->
