c# Stopky (STOP nebo PAUSE)

Zdravím,

udělal jsem si v c# winform stopky, zapnout mi jdou, ale nevím, jak udělat aby se zastavili (pause) a když dám zase start, tak aby jeli dál něco jako resume.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Threading;
using System.Diagnostics;

namespace Pocitadlo
{
    public partial class Form1 : Form
    {
        public int test = 0, mins, secs;
        Thread stopky;
       
        public Form1()
        {
            InitializeComponent();
        }

        public void START_Click(object sender, EventArgs e)
        {
            if (START.Text == "START")
            {
                START.Text = "STOP";
                cas.Enabled = true;
                stopky = new Thread(starter);
                stopky.Start();
            }
            else 
            {
                START.Text = "START";
                cas.Enabled = false;
                
            }
        }

        public void starter()
        {
            for (secs = 0; secs <= 59; secs++)
            {
                Thread.Sleep(200);
                if (mins < 9 && secs < 9)
                {
                    cas.BeginInvoke(new Action (() => cas.Text = String.Format("0{0}:0{1}", mins, secs)));
                }
                else if (mins < 9)
                {
                    if (secs == 59)
                    {
                        mins++;
                        cas.BeginInvoke(new Action(() => cas.Text = String.Format("0{0}:00", mins)));
                        secs = 0 - 1;
                    }
                    else
                    {
                        cas.BeginInvoke(new Action(() => cas.Text = String.Format("0{0}:{1}", mins, secs)));
                    }
                }
            }
        }

    }
}