job.cancel()

Job

launch

async

Job

suspend fun main() {
    class Bot() {
        val jobs = mutableListOf<Job>()
        init {
            val activeQuizzes = getActiveQuizzes()
            for(username in activeQuizzes) {
                start(username)
            }

        }
        private fun getActiveQuizzes(): List<String> {
            return listOf("User1", "User2")
        }
        fun start(username: String) {
            val job = Job()
            val scope = CoroutineScope(Dispatchers.Default + job)
            scope.launch {
                while (true) {
                    delay(500)
                    println("Delayed $username")
                }
            }
            jobs.add(job)
        }
        fun stop(id: Int) {
            println("Cancel job: $id")
            jobs[id].cancel()
        }
    }
    val bot = Bot()
    bot.start("User3")
    delay(5000)
    bot.stop(2)
    bot.jobs.joinAll()
}