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: screenshot.rs
    path of file: ./repos/glium/examples
    
    the code of the file until where you have to start completion: #[macro_use]
extern crate glium;
mod support;

use glium::index::PrimitiveType;
use glium::{Display, Surface};
use glutin::surface::WindowSurface;
use support::{ApplicationContext, State};

#[derive(Copy, Clone)]
struct Vertex {
    position: [f32; 2],
    color: [f32; 3],
}
implement_vertex!(Vertex, position, color);

struct Application {
    pub vertex_buffer: glium::VertexBuffer<Vertex>,
    pub index_buffer: glium::IndexBuffer<u16>,
    pub program: glium::Program,
}

impl ApplicationContext for Application {
    const WINDOW_TITLE:&'static str = "Gl
    
    fn draw_frame(&mut self, display: &Display<WindowSurface>) {
        let mut frame = display.draw();
        // For this example a simple identity matrix suffices
        let uniforms = uniform! {
            matrix: [
                [1.0, 0.0, 0.0, 0.0],
                [0.0, 1.0, 0.0, 0.0],
                [0.0, 0.0, 1.0, 0.0],
                [0.0, 0.0, 0.0, 1.0f32]
            ]
        };

        // Now we can draw the triangle
        frame.clear_color(0.0, 0.0, 0.0, 0.0);
        frame
            .draw(
                &self.vertex_buffer,
                &self.index_buffer,
                &self.program,
                &uniforms,
                &Default::default(),
            )
            .unwrap();
        frame.finish().unwrap();

        // Now we can read the front buffer and save it
        let image: glium::texture::RawImage2d<'_, u8> = display.read_front_buffer().unwrap();
        let image = image::ImageBuffer::from_raw(image.width, image.height, image.data.into_owned()).unwrap();
        let image = image::DynamicImage::ImageRgba8(image).flipv();
        image.save("glium-example-screenshot.png").unwrap();
    }