Perform some long-running initialization in background thread

BackgroundInit.kt

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    val application = this
    launch(UI) { // start a new coroutine in Android UI context
        // switch to background thread for some long-running initialization
        run(CommonPool) { AndroidThreeTen.init(application) }
        // then init UI 
        initUI()
    }
}