static void Main(string[] args)
        {
            EvenSubscriber sub = new EvenSubscriber();
            Random         r   = new Random();
            WaterTank      wt1 = new WaterTank(100, "WT1");
            WaterTank      wt2 = new WaterTank(10, "WT2");
            WaterTank      wt3 = new WaterTank(500, "WT3");
            WaterTank      wt4 = new WaterTank(50, "WT4");
            WaterTank      wt5 = new WaterTank(25, "WT5");


            wt1.ValueHasChanged += ReportChange;
            wt1.ValueHasChanged += sub.OnValueChanged;


            while (true)
            {
                wt1.Add(r.Next(5));
                wt2.Add(r.Next(5));
                wt3.Add(r.Next(5));
                wt4.Add(r.Next(5));
                wt5.Add(r.Next(5));
                Thread.Sleep(1000);
            }
        }
        static void Main(string[] args)
        {
            Random    r   = new Random();
            WaterTank wt1 = new WaterTank(100, "WT1");
            WaterTank wt2 = new WaterTank(10, "WT2");
            WaterTank wt3 = new WaterTank(500, "WT3");
            WaterTank wt4 = new WaterTank(50, "WT4");
            WaterTank wt5 = new WaterTank(25, "WT5");

            while (true)
            {
                wt1.Add(r.Next(5));
                wt2.Add(r.Next(5));
                wt3.Add(r.Next(5));
                wt4.Add(r.Next(5));
                wt5.Add(r.Next(5));
                Thread.Sleep(1000);
            }
        }