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: login-session.rs
    path of file: ./repos/rouille/examples
    
    the code of the file until where you have to start completion: #![allow(unreachable_code)]
#[macro_use]
extern crate rouille;

use rouille::Request;
use rouille::Response;
use std::collections::HashMap;
use std::io;
use std::sync::Mutex;

// This struct contains the data that we store on the server about each client.
#[derive(Debug, Clone)]
struct SessionData {
    login: String,
}

fn main() {
    // This example demonstrates how to create a website with a simple login form.

    // Small message so that people don't need to read the source code.
    // Note
    
fn handle_route_logged_in(request: &Request, _session_data: &SessionData) -> Response {
    router!(request,
        (GET) (/) => {
            // Show some greetings with a dummy response.
            Response::html(r#"You are now logged in. If you close your tab and open it again,
                              you will still be logged in.<br />
                              <a href="/private">Click here for the private area</a>
                              <form action="/logout" method="POST">
                              <button>Logout</button></form>"#)
        },

        (GET) (/private) => {
            // This route is here to demonstrate that the client can go to `/private` only if
            // they are successfully logged in.
            Response::html(r#"You are in the private area! <a href="/">Go back</a>."#)
        },

        _ => Response::empty_404()
    )
}