title: C# How to handle polymorphic models using NSwag
body: <p>I have a polymorphic model:</p>
  
  <pre><code>public class CreateOrderRequest
  {
      public List&lt;CreateOrderItem&gt; OrderItems { get; set; } 
  }
  
  /// &lt;summary&gt;
  /// Identifies a new item within an order
  /// &lt;/summary&gt;    
  [JsonConverter(typeof(CreateOrderLineJsonConvertor))]
  [KnownType("GetKnownTypes")]
  public class CreateOrderItem
  {
      public string OrderContext { get; set; }
      public string OrderItemType { get; set; }
  
      public static Type[] GetKnownTypes()
      {
          return new[]
          {
              typeof(OrderItemType1), typeof(OrderItemType2)
          };
      }
  }
  
  public class OrderItemType1: CreateOrderItem
  {
       public string Type1Prop {get;set;}
  }
  
  public class OrderItemType2: CreateOrderItem
  {
       public string Type2Prop {get;set;}
  }
  </code></pre>
  
  <p>Using NSwag (NSwag.AspNetCore) according to the documentation, I expected this to be enough so that documentation indicated / contained the order item types? But no...</p>
  
  <p><a href="https://i.stack.imgur.com/PDcMn.png" rel="noreferrer"><img src="https://i.stack.imgur.com/PDcMn.png" alt="enter image description here"></a></p>
  
  <p>Have i completely missed the point of what NSwag requires? I have the OrderItemType property. Do i need to get a discriminator involved? Where is this documented?</p>
  
  <p>TIA</p>