You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: shadow_caster_receiver.rs
    path of file: ./repos/bevy/examples/3d
    
    the code of the file until where you have to start completion: //! Demonstrates how to prevent meshes from casting/receiving shadows in a 3d scene.

use std::f32::consts::PI;

use bevy::{
    color::palettes::basic::{BLUE, LIME, RED},
    pbr::{light_consts, CascadeShadowConfigBuilder, NotShadowCaster, NotShadowReceiver},
    prelude::*,
};

fn main() {
    println
    
fn main() {
    println!(
        "Controls:
    C      - toggle shadow casters (i.e. casters become not, and not casters become casters)
    R      - toggle shadow receivers (i.e. receivers become not, and not receivers become receivers)
    L      - switch between directional and point lights"
    );
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup)
        .add_systems(Update, (toggle_light, toggle_shadows))
        .run();
}