eZ\Publish\Core\REST\Server\Controller\Role::assignRoleToUser() REST content

$request->getContent()

"RoleAssignInput":{
    "Role":{
        "xhr":{},
        "body":"{
            "Role": {
                "_media-type": "application/vnd.ez.api.Role+json",
                "_href": "/api/ezp/v2/user/roles/6",
                "identifier": "Subscriber",
                "Policies": {
                    "_media-type": "application/vnd.ez.api.PolicyList+json",
                    "_href": "/api/ezp/v2/user/roles/6/policies"
                }
            }
        }",
        "document":{
            "Role":{
                "_media-type":"application/vnd.ez.api.Role+json",
                "_href":"/api/ezp/v2/user/roles/6",
                "identifier":"Subscriber",
                "Policies":{
                    "_media-type":"application/vnd.ez.api.PolicyList+json",
                    "_href":"/api/ezp/v2/user/roles/6/policies"
                }
            }
        },
        "status":200,
        "headers":"Date: Mon, 28 Sep 2015 12:33:18 GMT
                   Server: Apache/2.4.10 (Debian)
                   Cache-Control: no-cache
                   Accept-Patch: application/vnd.ez.api.RoleInput+json
                   X-Cache-Debug: 1
                   Vary: Cookie,Authorization
                   X-Debug-Token: fe2991
                   X-Debug-Token-Link: /_profiler/fe2991
                   Content-Length: 336
                   Keep-Alive: timeout=5, max=95
                   Connection: Keep-Alive
                   Content-Type: application/vnd.ez.api.Role+json"
    },
    "limitation":{}
}