[question] Process complex data such as a product import #256

For a product import, each product can have multiple variants, each variant contains its own sets of fields. I wonder how to best work around this issue without using multiple files (products.csv and variants.csv) as it will be quite difficult for end users to understand and manage.

One possible solution comes to mind is to use multiple rows, for example the first row will be used for product, then the following rows will be used for variants until we hits the next product (perhaps detected by the present of a different id value in the id column).

Is there anyway we can do something like that? Perhaps by writing custom Writer?