Coroutines API for sequential displaying of balloons as alternative for Relay API

[heckfyxe]

Relay API becomes harder to maintain when app has complex logic for balloons. Maybe coroutines could simplify it.

Sequential ordered balloons:

balloon1.awaitAlignBottom(view1)
balloon2.awaitAlignTop(view2)

Balloons displayed sequentially one by one. Methods suspend until balloon isn't dismissed.

Sequential unordered balloons:

viewModel.user.observe(viewLifecycleOwner) {
    setupUser(it)
    lifecycleScope.launch {
        userBalloon.awaitAlignLeft()
    }
}
viewModel.items.observe(viewLifecycleOwner) {
    adapter.submitList(it)
    lifecycleScope.launch {
        itemBalloon.awaitAlignBottom()
    }
}

Sometimes app has to show balloon as soon as it loads required data. Problems appears when you have bunch of data to load. With current api you have to write some boilerplate to ensure that only one balloon is displayed.