【Rust日报】2020-03-14 更紧凑的`Cow`，Confy 0.4

use beef::Cow;

let borrowed = Cow::borrowed("Hello");
let owned = Cow::from(String::from("World"));

assert_eq!(
    format!("{} {}!", borrowed, owned),
    "Hello World!",
);

// beef::Cow is 3 word sized, while std::borrow::Cow is 4 word sized
assert!(std::mem::size_of::<Cow<str>>() < std::mem::size_of::<std::borrow::Cow<str>>());

#[derive(Default, Debug, Serialize, Deserialize)]
struct MyConfig {
    version: u8,
    api_key: String,
}

fn main() -> Result<(), ::std::io::Error> {
    let cfg: MyConfig = confy::load("my-app-name")?;
    dbg!(cfg);
    Ok(())
}