How to expose HTTP status codes for logs?

I’d like to populate meta.HTTP.Response.status_code, but I’m not sure how to do this. Right now fly logs -j gives me this:

{
    "level": "info",
    "instance": "f1460fbc",
    "message": "Got request to /api/prompts { user_id: '46', limit: '15', queue: 'true' }",
    "region": "ord",
    "timestamp": "2022-09-02T22:45:43.996113822Z",
    "meta": {
        "Instance": "f1460fbc",
        "Region": "ord",
        "Event": {
            "Provider": "app"
        },
        "HTTP": {
            "Request": {
                "ID": "",
                "Method": "",
                "Version": ""
            },
            "Response": {
                "status_code": 0
            }
        },
        "Error": {
            "Code": 0,
            "Message": ""
        },
        "URL": {
            "Full": ""
        }
    }
}