title: BSON serialization in C# driver for MongoDB
body: <p>I just started playing with MongoDB and official c# driver for it. And I have a small question regarding objects serialization. For example we have a classes: </p>
  
  <pre><code>public class User
  {
      public string Name;
  
      public List&lt;Comment&gt; Comments = new List&lt;Comment&gt;(){ new Comment() };
      public List&lt;Card&gt; Cards = new List&lt;Card&gt;() { new Card() };
  }
  
  public class Comment
  {
      public string Id;
      public string Text;
  }
  
  public class Card
  {
      public string Id;
      public string Text;
  }
  </code></pre>
  
  <p>I want to get serialized Cards collection within User, but Comments collection like DBRef. Is it possible to achieve it with latest standard c# driver? It will be really cool to use some attribute like:</p>
  
  <pre><code>public class User
  {
      public string Name;
  
      [UseDBRef]
      public List&lt;Comment&gt; Comments = new List&lt;Comment&gt;(){ new Comment() };
  
      public List&lt;Card&gt; Cards = new List&lt;Card&gt;() { new Card() };
  }
  </code></pre>