static long stupidFib_collab(ICollab collab, int n) {
  ret collab_computeLong(collab,
    receiver -> stupidFib_collab(collab, n, receiver));
}

svoid stupidFib_collab(ICollab collab, int n, LongConsumer continuation) {
  if (n < 3) ret with continuation.get(1L);
  
  LongPairCollector collector = new {
    void complete(int a, int b) {
      continuation.get(a+b);
    }
  };
  
  collab.addWork(-> stupidFib_collab(collab, n-1, collector.setterForA()));
  collab.addWork(-> stupidFib_collab(collab, n-2, collector.setterForB()));
}