使用Bevy，如何在创建后获取和设置窗口信息？

use bevy::prelude::*;

fn main() {
    App::build()
        .add_plugins(DefaultPlugins)
        .add_startup_system(setup.system())
        .run();
}

fn setup(commands: &mut Commands, windows: Res<Windows>) {
    let window = windows.get_primary().unwrap();
    let width = window.width();
    let height = window.height();
    println!("Window width: {}, height: {}", width, height);
}

use bevy::prelude::*;

fn main() {
    App::build()
        .add_plugins(DefaultPlugins)
        .add_startup_system(setup.system())
        .run();
}

fn setup(commands: &mut Commands, mut windows: ResMut<Windows>) {
    let window = windows.get_primary_mut().unwrap();
    window.set_resolution(800, 600);
}