public void Work(StockController stockController, TimeSpan workDay)
        {
            var random = new Random(this.Name.GetHashCode());
            var start  = DateTime.Now;

            while (DateTime.Now - start < workDay)
            {
                Thread.Sleep(random.Next(100));
                var buy      = (random.Next(6) == 0);
                var itemName = Program.AllShirtNames[random.Next(Program.AllShirtNames.Count)];
                if (buy)
                {
                    var quantity = random.Next(9) + 1;
                    stockController.BuyStock(this, itemName, quantity);
                    DisplayPurchase(itemName, quantity);
                }
                else
                {
                    var success = stockController.TrySellItem(this, itemName);
                    DisplaySaleAttempt(success, itemName);
                }
            }
            Console.WriteLine("SalesPerson {0} signing off", this.Name);
        }