Как реализовать ConcurrentHashSet в .Net

    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
    Calendar cal = Calendar.getInstance();
    System.out.println("time => " + dateFormat.format(cal.getTime()));

    String time_str = dateFormat.format(cal.getTime());

    String[] s = time_str.split(" ");

    for (int i = 0; i < s.length; i++) {
         System.out.println("date  => " + s[i]);
    }

    int year_sys = Integer.parseInt(s[0].split("/")[0]);
    int month_sys = Integer.parseInt(s[0].split("/")[1]);
    int day_sys = Integer.parseInt(s[0].split("/")[2]);

    int hour_sys = Integer.parseInt(s[1].split(":")[0]);
    int min_sys = Integer.parseInt(s[1].split(":")[1]);

    System.out.println("year_sys  => " + year_sys);
    System.out.println("month_sys  => " + month_sys);
    System.out.println("day_sys  => " + day_sys);

    System.out.println("hour_sys  => " + hour_sys);
    System.out.println("min_sys  => " + min_sys);