runthe Akka stream, since
Futures start immediately. Put the
run(args: List[String]): IO[ExitCode]method.
IOAppis that it takes care of running the
println, so you should see your output fine.
Future[Done], which has a thread that prints the ticks, right?
ExitCode.Failure, IIRC, when the JVM halts, Linux (or macOS or whatever) will have its "errno" be -1, or somesuch.