Kompilierzeit-Erzwingung von API-Zuständen durch das Typestate-Muster

pub struct Uninitialized;
pub struct Connected {
    pub socket_id: u32,
}
 
pub struct Connection<State> {
    pub host: String,
    pub state: State,
}
 
impl Connection<Uninitialized> {
    pub fn new(host: &str) -> Self {
        Self {
            host: host.to_string(),
            state: Uninitialized,
        }
    }
 
    pub fn connect(self) -> Connection<Connected> {
        Connection {
            host: self.host,
            state: Connected { socket_id: 101 },
        }
    }
}
 
impl Connection<Connected> {
    pub fn send(&self, data: &[u8]) {
        println!("Sending to socket {}: {:?}", self.state.socket_id, data);
    }
}