-- the arc: spawn/send/actor M — an actor is a class with receive(msg: M);
-- messages MOVE; delivery is one message at a time; main's return reaps
-- idle actors clean (ASan gate covers this fixture too).

class Note {
  text: Text
}

class Logger {
  prefix: Text
  seen: Int
  fn receive(msg: Note) {
    self.seen = self.seen + 1;
    print("${self.prefix}${msg.text} #${self.seen}");
  }
}

fn main() -> Int {
  let a: actor Note = spawn Logger { prefix: "log: ", seen: 0 };
  send(a, Note { text: "first" });
  send(a, Note { text: "second" });
  let n = Note { text: "third" };
  send(a, n);
  -- the scheduler drains actor messages when main yields or ends; a
  -- backward-jump loop hands turns over under the default budget? No:
  -- default budget is 4000 — force turns with a tiny spin so delivery
  -- interleaves before main returns
  let i = 0;
  while i < 20000 {
    i = i + 1;
  }
  print("main done");
  return 0;
}