title: How to find out an object has disposed?
body: <p>I have a multi-threaded application and a <code>CancellationToken</code> is used as a shared object. Every thread can trigger it to tell the other threads the job is cancelled. Then one thread does the clean-up and disposes every object like this <code>CancellationToken</code>. Then if a thread tries to use it, an exception is raised: </p>
  
  <blockquote>
    <p>The CancellationTokenSource has been disposed.</p>
  </blockquote>
  
  <p>How can I find out an object is disposed before using it?</p>