Code shared from the Rust Playground

playground.rs

use serde::Deserialize;
use serde_json;
use std::marker::PhantomData;

#[derive(Deserialize, Debug)]
struct Ping<'a> {
    #[serde(borrow)]
    ping: &'a str,
}

fn handle<'a: 'de, 'de, T: Deserialize<'de>, Callback: Fn(T)>(msg: &'a str, callback: Callback) {
    let res: T = serde_json::from_str(&msg).unwrap();
    callback(res);
}

fn main() {
    let callback = |p: Ping| println!("{:?}", p);
    let msg = format!("{{\"ping\":\"{}\"}}", "abcdefg");
    handle(&msg, callback);
}