title: Can you use interfaces as DataMembers in WCF?
body: <p>Can you do this?</p>
  
  <pre><code>[DataContract]
  public class RegisterEndpointRequest : NotificationRegistrationServiceRequest
  {
      [DataMember]
      public IEndpoint Endpoint { get; set; }
  }
  </code></pre>
  
  <p>Notice the member Endpoint is an interface (<code>IEndpoint</code>), not a class. Will WCF allow this?</p>