toJson method
Implementation
@override
Map<String, dynamic> toJson() => <String, dynamic>{
'invoice_chat_id': invoiceChatId,
'invoice_message_id': invoiceMessageId,
'currency': currency,
'total_amount': totalAmount,
'subscription_until_date': subscriptionUntilDate,
'is_recurring': isRecurring,
'is_first_recurring': isFirstRecurring,
'invoice_name': invoiceName,
'@type': constructor,
};