magento2 – Magento 2 REST API – How to add product custom attribute type file upload to a product when adding a product

I’m working on a project where my product has some datasheets that has to be uploaded to the website. Right now I’ve created one product attribute named datasheet with attribute type file upload. I’m able to create product using REST API. But the problem is I cannot able to add this files through API as I’m confused how to add this through it.

I know that we can use

"custom_attributes": [ { "attribute_code": "item_ship_day", "value": "Ships in 2 days" }, }

works for normal attributes. But what about file upload