public creating_and_updating_invoices_with_manual_invoicing()
        {
            var customerService    = new StripeCustomerService(Cache.ApiKey);
            var invoiceItemService = new StripeInvoiceItemService(Cache.ApiKey);
            var invoiceService     = new StripeInvoiceService(Cache.ApiKey);

            var CustomerCreateOptions = new StripeCustomerCreateOptions
            {
                Email = "*****@*****.**",
            };
            var Customer = customerService.Create(CustomerCreateOptions);

            var InvoiceItemCreateOptions = new StripeInvoiceItemCreateOptions
            {
                Amount     = 1000,
                Currency   = "usd",
                CustomerId = Customer.Id
            };
            var InvoiceItem = invoiceItemService.Create(InvoiceItemCreateOptions);

            var InvoiceCreateOptions = new StripeInvoiceCreateOptions
            {
                Billing      = StripeBilling.SendInvoice,
                DaysUntilDue = 7,
            };

            InvoiceCreated = invoiceService.Create(Customer.Id, InvoiceCreateOptions);

            var InvoiceUpdateOptions = new StripeInvoiceUpdateOptions
            {
                Paid = true,
            };

            InvoiceUpdated = invoiceService.Update(InvoiceCreated.Id, InvoiceUpdateOptions);
        }