title: MessageSource.MessageSink is null
body: <p>This is what I have:</p>
  
  <pre><code>Message msg = new Message(SeverityType.Error,"xx","xx", "xx");
  IMessageSink sink = MessageSource.MessageSink;
  sink.Write(msg);   // NullReferenceException (sink == null)
  </code></pre>
  
  <p>While I was doing some digging online, it seems like every example is using MessageSource.MessageSink.Write(msg), and I'm confused why my code doesn't work.</p>
  
  <p>Any help is appreacited.</p>