Function generate_access_log_message 

pub fn generate_access_log_message(
    request_parts: &Parts,
    socket_data: &SocketData,
    auth_user: Option<&str>,
    timestamp_str: &str,
    status_code: u16,
    content_length: Option<u64>,
    log_format: Option<&str>,
    log_json_props: Option<&HashMap<String, ServerConfigurationValue>>,
) -> String