X11rb DPMS Help

This might be a bit of a noobish question for here, so sorry if it's the wrong place for it. I'm working on a personal project and part of what I want to do is turn the screen on and off when I get certain events. I've got it working using std::command and running xset -display :0 dpms force off/on. I'd like to try to use x11rb to see if that's faster. When I use the code below nothing happens, but I don't get any errors, so I don't know why it's not working. I'm not too experienced at using x in code. If anyone knows, what I'm doing wrong, I'd really appreciate your help.

use x11rb::{self, protocol::dpms};

fn main() {
    let (conn, screen_num) = x11rb::connect(Some(":0")).unwrap();
    dpms::force_level(&conn, dpms::DPMSMode::OFF);

You can use the VoidCookie::check method to check for errors. This returns a Result, so you can either use unwrap() to print the error and panic, or you could match on the result if you want to do something else with it.

    let reply = dpms::force_level(&conn, dpms::DPMSMode::OFF).unwrap();

It looks like just checking the void cookie at all fixed the problem. Thanks for your help.