private async Task CompletePurchaseAsync(double changeDue, Product product)
{
_vendingMachineDisplay.PrintGratitude();
ReturnChange(changeDue);
_vendingMachineHardware.EjectItem(product);
await Task.Delay(800); //Delay to simulate the machine resetting. Not really idea but there you have it.
_vendingMachineDisplay.PrintInsertCoin();
}
