GoBack.kt

fun Dispatcher.goBack() {
    popLastShowingState()//current state is what we are currently showing
    dispatchShow(popLastShowingState())
}

fun popLastShowingState(): State {
    if(!showEvents.empty()) Timber.d("popping "+showEvents.peek())
    return if (showEvents.isEmpty()) State.BackStackEmpty else showEvents.pop()
}