处置时为什么Mutex不会被释放？

I have the following code:

我有以下代码：

using (Mutex mut = new Mutex(false, MUTEX_NAME))
{
    if (mut.WaitOne(new TimeSpan(0, 0, 30)))
    {
       // Some code that deals with a specific TCP port
       // Don't want this to run at the same time in another process
    }
}
using (M