Read a toml file config and download a binary file with libcurl

lib.toml

[lib]
name        = "SFML"
filename    ="SFML-2.5.1-windows-vc15-64-bit.zip"
url         ="https://github.com/SFML/SFML/releases/download/2.5.1/SFML-2.5.1-windows-vc15-64-bit.zip"

read_toml_get_fil.rs

use curl::easy::Easy;
use std::fs::File;
use std::io::prelude::*;
use serde::{Deserialize};

#[derive(Deserialize)]
struct Lib {
    name: String,
    filename: String,
    url: String,
}

#[derive(Deserialize)]
struct Dep {
    lib:Lib,
}


fn main() -> std::io::Result<()> {

   let mut f = File::open("lib.toml")?;
    let mut buffer = Vec::new();

    // read the whole file
    f.read_to_end(&mut buffer)?;

    let dep:Dep = toml::from_slice(&buffer).unwrap();     

    println!("{:#?}", dep.lib.name); 
    println!("{:#?}", dep.lib.filename); 
    println!("{:#?}", dep.lib.url);   

    let mut dst = Vec::new();
    let mut easy = Easy::new();
    easy.url(&dep.lib.url).unwrap();
    let _redirect = easy.follow_location(true);

    {
        let mut transfer = easy.transfer();
        transfer.write_function(|data| {
            dst.extend_from_slice(data);
            Ok(data.len())
        }).unwrap();
        transfer.perform().unwrap();
    }
    {
        let mut file = File::create(dep.lib.filename)?;
        file.write_all(dst.as_slice())?;
    }

    Ok(())
}