pub struct Threadable<J> where J:Clone{
    slowdown_signal: Arc<AtomicBool>,
    semaphore: Arc<Semaphore>,
    termination_signal: Lockstep<Option<String>>,
    time: Lockstep<SystemTime>,
    readonly_data: Arc<J>
}

impl<J> Threadable<J> {
    pub fn create(starting_th: isize, max_th: isize, data: J) -> Threadable<J> {
        let slowdown = AtomicBool::new(false);
        let slowdown_signal: Arc<AtomicBool> = Arc::new(slowdown);
        let semaphore: Arc<Semaphore> = prepare_semaphore(starting_th, max_th);
        let termination_signal: Lockstep<Option<String>> = Arc::new(Mutex::new(None));
        let time: Lockstep<SystemTime> = Arc::new(Mutex::new(SystemTime::now()));
        let data = Arc::new(data);
        Threadable{slowdown_signal: slowdown_signal, semaphore:semaphore,
            termination_signal: termination_signal, time: time,  readonly_data: data}
    }

    pub fn clone(&self) -> Threadable<J> {
        ...
    }
...
}