Where to place the body in a SharePoint Designer workflow POST request

Question

I am constructing a REST API call in a SharePoint Designer workflow, to rename a file in a library.

I'm using the Call HTTP Web Service action with the POST method, and I've set this to the API URL (https://example.sharepoint.com/_api/web/whatever...) and request contains my request headers (Content-type: application/json, amongst others):

However, I'm not sure where to put the dictionary that contains my JSON request body. Should it go in the request headers, and if so what should I name it? If not then where should I put it?

Answer 1

After Googling 'body' rather than 'payload' (as per my original question title) I found this blog post linked from a MSDN thread.

It says that you need to select Advanced Properties from the ribbon, and set the RequestHeaders and RequestContent options explicitly.