fn main() {
    use std::net::SocketAddr;
    use std::sync::{Arc, Mutex};

    let data: Arc<Mutex<Option<SocketAddr>>> = Arc::new(Mutex::new(None));

    {
        let mut data = data.lock().unwrap();
        if let Some(ip) = *data {
            println!("data has ip: {}", ip);
        } else {
            println!("data has no ip");
            *data = Some("1.1.1.1:443".parse().unwrap());
        }
    }

    {
        let mut data = data.lock().unwrap();
        if let Some(ip) = *data {
            println!("data has ip: {}", ip);
        } else {
            println!("data has no ip");
            *data = Some("1.1.1.1:443".parse().unwrap());
        }
    }
}