toJson method
Implementation
core.Map<core.String, core.dynamic> toJson() => {
if (offerId != null) 'offerId': offerId!,
if (packageName != null) 'packageName': packageName!,
if (productId != null) 'productId': productId!,
if (purchaseOptionId != null) 'purchaseOptionId': purchaseOptionId!,
};