then:
        1 * fooListener1.foo("param")
        0 * _
    }

    def listenersReceiveMessagesInSameOrderRegardlessOfGeneratingThread() {
        given:
        def events1 = events("a", 20)
        def events2 = events("b", 20)
        def events3 = events("c", 20)
        def received1 = new CopyOnWriteArrayList<String>()
        def received2 = new CopyOnWriteArrayList<String>()