Ingrid shipping plugin

How do I add cart attributes to the Ingrid session?

When Ingrid is enabled as a plugin, calls to PUT checkout-fields (ShopAPI) and PUT payment-fields (CheckoutAPI) will listen to the value ingridAttributes inside the additionalFields. This field should contain an array of strings, like this:

{
  "additionalFields": {
    "ingridAttributes": ["attribute1", "attribute2"]
  }
}

These attributes will then be set on the Ingrid cart as cart attributes.