Retrieve an InvoiceFacades: pos, merchantOverview Get a specific invoice by ID. Parameters ParameterDescriptioninvoiceIdThe ID of the invoice to retrieve. Example Java (Merchant Facade)Java (POS Facade)Invoice invoice = bitpay.getInvoice("QrPWSMkq594kQfJex28S7X"); Invoice invoice = bitpay.getInvoice("QrPWSMkq594kQfJex28S7X", Facade.POS, false);