Adding attachment to content

Summary

How can I add attachments to content using rest api

Content

I'm trying to develop an application that creates contents on my KA. First, I was only creating and publishing contents with text fields, but now I want to add attachments to the contents, even using UPDATE or CREATE service.

I did not found on documentation how can I do this. 

Need some help to create this integration, anybody can help me ?

Version

KA 19C