sample_of_error_in_coffee_machine_2.kt

fun brewCoffee(): Single<Coffee> {
    return Single
       .fromCallable {
           // Simulate the machine takes random time up to 5s to brew a coffee.
           Thread.sleep(5 * 60 * 1000 * Math.random())
           // The machine have chance to crash with no reason.
           if (0.5f < Math.random()) throw RuntimeException()
           return@Callable Coffee()
       }
       .subscribeOn(Schedulers.io())
}