private static void MultiThreadSynergicWithSemaphore()  {   //0表示創建Semaphore時，擁有可用信號量數值   //1表示Semaphore中，最多容納信號量數值   Semaphore semaphore = new Semaphore(0, 1);   Thread thread1 = new Thread(() =>   {    //線程首先WaitOne等待一個可用的信號量    semaphore.WaitOne();    //在得到信號量后，執行下面代碼內容    Console.WriteLine("thread1 work");    Thread.Sleep(5000);    //線程執行完畢，將獲得信號量釋放（還給semaphore）    semaphore.Release();   });   Thread thread2 = new Thread(() =>   {    semaphore.WaitOne();    Console.WriteLine("thread2 work");    Thread.Sleep(5000);    semaphore.Release();   });   thread2.Start();   thread1.Start();   //因在創建Semaphore時擁有的信號量為0   //semaphore.Release(1) 為加入1個信號量到semaphore中   semaphore.Release(1);  }