External User Name not considered when passing event file

[p2a8t4a5a]

-H 'Content-Type: application/json' -d '{"event": "file", "external_user_name":"TestName", "content": {"data": "iVBORw0KGgoAAAANSUhEUgAAABQAAAAaCAYAAAC3g3x9AAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJ\nbWFnZVJlYWR5ccllPAAAAElJREFUeNpiYECA/UD8n0y8nwENUGIYTkOpAhihplMNMFHbhVQ3kIVA\ncOAD/0k1kAFP+DIO3UgZTYej6XA0HY6mw9F0CAEAAQYAk/gtCSEUikYAAAAASUVORK5CYII=\n", "content_type": "image/png", "file_name": "test.png" }}'