toJson method
Converts a PreCheckoutQuery object to a JSON object
Implementation
Map<String, dynamic> toJson() {
return {
'id': id,
'from': from.toJson(),
'currency': currency,
'total_amount': totalAmount,
'invoice_payload': invoicePayload,
'shipping_option_id': shippingOptionId,
'order_info': orderInfo?.toJson(),
}..removeWhere(_nullFilter);
}