object Scheduler {
    private val actual by lazy { Scheduler().apply(Scheduler::start) }

    fun register(cron: String, task: suspend CoroutineScope.() -> Unit) {
        require(SchedulingPattern.validate(cron)) { "Invalid cron string $cron" }
        actual.schedule(cron) {
            runBlocking(Dispatchers.IO, task)
        }
    }
}