CPU負荷を消費せずタイマー割り込みを待つ方法(C#)

using System;
using System.Drawing;
using System.Windows.Forms;
using System.Threading;

class Form1 : Form {
    static void Main() {
        Application.Run(new Form1());
    }
    
    Label label1;
    Form1() {
        label1 = new Label();
        Button btn1 = new Button();
        btn1.Text = "Start";
        btn1.Left = label1.Width;
        btn1.Click += new EventHandler(Start);
        Button btn2 = new Button();
        btn2.Text = "Stop";
        btn2.Left = label1.Width + btn1.Width;
        btn2.Click += new EventHandler(Stop);
        Controls.AddRange(new Control[]{ label1, btn1, btn2 });
        this.Closing += new System.ComponentModel.CancelEventHandler(ClosingForm);
    }
    
    void ClosingForm(object o, System.ComponentModel.CancelEventArgs e) {
        timer1.Change(Timeout.Infinite, 0);  
    }
    
    delegate void SetTextDelegate(string data);
    
    void SetText(string data) {
        label1.Text = data;
    }
    
    void Tick(object state) {
        SetTextDelegate std = new SetTextDelegate(SetText);
        this.Invoke(std, new object[]{ DateTime.Now.ToLongTimeString() });
    }

    System.Threading.Timer timer1;
    void Start(object o, EventArgs e) {
        timer1 = new System.Threading.Timer(
            new TimerCallback(Tick), null, Timeout.Infinite, 1000);
        timer1.Change(0, 1000);
        BackColor = Color.Green;
    }

    void Stop(object o, EventArgs e) {
        timer1.Change(Timeout.Infinite, 0);
        BackColor = SystemColors.Control;
    }
}