for (int i = 0; i < 5; i++)
            {
                var thr = new Thread(new ThreadStart(new MethodInvoker(delegate
                 {
                     for (int t = 0; t < 100000; t++)
                     {
                         this.Invoke(new MethodInvoker(delegate
                         {
                             richTextBox1.Invoke((System.Action)(() => { richTextBox1.ScrollToCaret(); richTextBox1.AppendText(t.Tostring() + Environment.NewLine); }));
                         }));
                     }
                 })));
                thr.IsBackground = true;
                thr.Start();
            }
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