gistfile1.txt

using System;
using System.Threading;
using System.Threading.Tasks;

class C
{
	public static void Main ()
	{
		var tsc = new TaskCompletionSource<int> ();

		Thread t1 = new Thread (() => {
			while (true) {
				tsc.TrySetCanceled ();
			}
		});
/*
		Thread t2 = new Thread (() => {
			while (true) {
				tsc.TrySetResult (2);
			}
		});
*/
		Thread t3 = new Thread (() => {
			while (true) {
				tsc.TrySetException (new NotImplementedException ());
			}
		});

		t1.Start ();
		//t2.Start ();
		t3.Start ();

		while (true) {
			t1.Suspend ();
	//		t2.Suspend ();
			t3.Suspend ();
			tsc = new TaskCompletionSource<int> ();
			t1.Resume ();
	//		t2.Resume ();
			t3.Resume ();
		}
	}
}