Listening for PostgreSQL table modification events in a loop

I am trying to write a client which will listen for events from PostgreSQL in a loop. Below is something I could come up with (considering I am beginner in rust)

pub fn future(&self) -> Result<(), ()> {
    let url = "postgresql://root:root@127.0.0.1/test";
    Connection::connect(url, TlsMode::None)
        .map_err(|error| {
            println!("{:?}", error);
        })
        .and_then(|conn: Connection| {
            conn.execute("LISTEN modify_event", &[])
                .expect("Could not send LISTEN");
            Ok(conn)
        })
        .and_then(|conn: Connection| {
            let notifications = conn.notifications();
            let mut blocking_iter = notifications.blocking_iter();

            println!("Waiting for notifications...");
            blocking_iter
                .next()
                .map(|data| match data {
                    Some(data) => serde_json::from_str::<User>(&data.payload)
                        .map_err(|error| {
                            println!("Postgre data deserialization error: {}", error);
                        })
                        .map(|subscriber| {
                            println!("{:?}", subscriber);
                        })
                        .unwrap(),
                    _ => (),
                })
                .map_err(|error| {
                    println!("{:?}", error);
                })
        })
}

And in some other module, I would spawn this future.

However, I am not able to figure out how to run this listener in loop. Also, could anyone please provide me a simple example to do the same with tokio runtime in tokio-postgres (considering https://github.com/tokio-rs/tokio/issues/418).