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: custom_gltf_vertex_attribute.rs
    path of file: ./repos/bevy/examples/2d
    
    the code of the file until where you have to start completion: //! Renders a glTF mesh in 2D with a custom vertex attribute.

use bevy::{
    gltf::GltfPlugin,
    prelude::*,
    reflect::TypePath,
    render::{
        mesh::{MeshVertexAttribute, MeshVertexBufferLayoutRef},
        render_resource::*,
    },
    sprite::{Material2d, Material2dKey, Material2dPlugin, MaterialMesh2dBundle, Mesh2dHandle},
};

/// This vertex attribute supplies barycentric coordinates for each
    
fn main() {
    App::new()
        .insert_resource(AmbientLight {
            color: Color::WHITE,
            brightness: 1.0 / 5.0f32,
        })
        .add_plugins((
            DefaultPlugins.set(
                GltfPlugin::default()
                    // Map a custom glTF attribute name to a `MeshVertexAttribute`.
                    .add_custom_vertex_attribute("_BARYCENTRIC", ATTRIBUTE_BARYCENTRIC),
            ),
            Material2dPlugin::<CustomMaterial>::default(),
        ))
        .add_systems(Startup, setup)
        .run();
}