Cargo.toml:
[package]
...
[dependencies]
s_app_dir = "*" # or semantic versioning
main.rc:
extern crate s_app_dir;
use s_app_dir::{AppDir, XdgDir};
fn main() {
let app_dir = AppDir::new("foo-bar-app");
println!("{:?}", app_dir.xdg_dir(XdgDir::Config));
}