title: Exception with null message
body: <p>I found that exception message can't be null in C#, and after trying this </p>
  
  <pre><code> var ex = new Exception(null);
   Console.WriteLine(ex.Message);
  </code></pre>
  
  <p>I get the following message:</p>
  
  <blockquote>
    <p>Exception of type 'System.Exception' was thrown.</p>
  </blockquote>
  
  <p>But, in this case,</p>
  
  <pre><code> var ex = new Exception(string.Empty);
   Console.WriteLine(ex.Message);
  </code></pre>
  
  <p>the message is just empty.</p>
  
  <p>How this can be explained? Do you think this is expected behavior? </p>