#[derive(MsgId, Serialize, Deserialize, Debug)]
pub struct Add(pub i32, pub i32);
impl FnRemote for Add {
    type Output = i32;
}
#[derive(MsgId, Serialize, Deserialize, Debug)]
pub struct TryMultiply(pub i32, pub i32);
impl FnRemote for TryMultiply {
    type Output = Result<i32, ()>;
}

async fn add(args: &Add) -> i32 {
    args.0 + args.1
}
async fn try_multiply(args: &TryMultiply) -> Result<i32, ()> {
    Ok(args.0 * args.1)
}
let app = Router::new()
    .http_rpc_route("/http", add)
    .http_rpc_route("/http", try_multiply);
Server::bind(&SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 9090))
    .serve(app.into_make_service())
    .await
    .unwrap();

let connection = http::Connection::new(&format!("https://127.0.0.1:9090/api"));
let result = Add(1, 2).call(&connection).await?;
assert_eq!(3, result);