Setting Page Level Restrictions with Confluence REST API (6.10.1)

[Bill]

Either on page creation (also with the REST API), or after the fact (I'm indifferent on the method)

Can someone post an example payload?

I've attempted to do this on page creation

{
 "type": "page",
 "space": {
    "key": "SPACEKEY"
 },
 "title": "My Page",
 "body": {
    "storage": {
       "value": "Some Content",
       "representation": "storage"
    }
 },
 "restrictions": {
    "user": [
       {
          "type": "known",
          "username": "johndoe"
       }
    ]
  }
 }

I've also attempted to do this after the fact with the method shown here: (https://community.atlassian.com/t5/Confluence-questions/How-can-i-set-page-restrictions-read-update-with-Confluence/qaq-p/694096)

using the suggestion from @Hasnae with no luck. (The endpoint suggested doesn't actually exist.)

How does one set a page level restriction to a specific user with the API?

[Bill]

Apparently there is ZERO documentation on this but the answer is here:

https://community.atlassian.com/t5/Answers-Developer-Questions/Set-Page-Restrictions-using-Confluence-REST-API-v5-5/qaq-p/487662