iterator producer.cs

class Producer {
    public static IEnumerator Coroutine(int[,] source, Coordinator<int[]> coordinator) {
        Console.WriteLine("producer started");
        for(var i = 0; i < source.GetLength(0); i++) {
            coordinator.State = new int[source.GetLength(1)];
            for(var j = 0; j < source.GetLength(1); j++) {
                coordinator.State[j] = source[i, j];
                Console.WriteLine("read {0} from [{1},{2}]", source[i, j], i, j);
            }
            Console.WriteLine("yielding to consumer");
            yield return null;
        }
        coordinator.State = new int[0];
        Console.WriteLine("producer finished");
    }
}