title: How to pass IUnknown argument to a COM interface using C#?
body: <p>I have a COM interface defined like this </p>
  
  <pre><code>interface Client : IUnknown
  {
      [id(1)] HRESULT GetSomething
      (
          enum SomeID someID,
          [out] IUnknown  **pUnknown
      );
  };
  </code></pre>
  
  <p>How can I pass <code>IUnknown</code> object using C#?</p>