We are trying to have a custom solution for conversion tracking and we want to track `InitiateCheckout` events reliably. We found the `checkouts/create` webhook and it seems to fire correctly. The only problem is that we can't use the data there as it's not labeled with any detail to identify this event with a specific user session.
I'm familiar with the property `cart_token` and we can use it to match the user session with the cart token but the problem is that this value doesn't exist when the user clicks on the "Buy It NOW" button as there is no cart connected.
Is there any way to receive something on the webhook payload to identify the current user? We don't mind building a custom Shopify App to make it work, we just can't find any valid way doing it.