compose_launched_effect_2.kt

@Composable
fun TimerScreen1() {
    Column(
        modifier = Modifier
            .fillMaxSize(),
        horizontalAlignment = Alignment.CenterHorizontally
    ) {
        var timerDuration by remember {
            mutableStateOf(1000L) // default value = 1 sec
        }
        Button({
            timerDuration -= 1000
        }) {
            Text("-1 second")
        }
        Text(timerDuration.toString())
        Button({
            timerDuration += 1000
        }) {
            Text("+1 second")
        }
        Timer(timerDuration = timerDuration)
    }
}

@Composable
fun Timer(timerDuration: Long) {
    LaunchedEffect(key1 = timerDuration, block = {
        try {
            startTimer(timerDuration) {
                println("Timer ended")
            }
        } catch (ex: Exception) {
            println("timer cancelled")
        }
    })
}