addToCart method
Add item to cart.
Adds a product to the shopping cart with the specified quantity.
sku
the product's SKU to add
quantity
the quantity to add
productOption
optional product options (size, color, etc.)
Returns true
if item was added successfully, false
otherwise.
Implementation
Future<bool> addToCart(
String sku,
int quantity, [
Map<String, dynamic>? productOption,
]) {
throw UnimplementedError('addToCart() has not been implemented.');
}