title: Calling IMappingEngine.Map inside custom mapping
body: <p>With AutoMapper, when using ConvertUsing to define a custom mapping for a type that is a container, I often need to call IMappingEngine.Map inside the mapping function. This is necessary because it allows-me to reuse the definition of the child mapping.</p>
  
  <pre><code>CreateMap&lt;Order, OrderModel&gt;()
      .ConvertUsing(o =&gt; new OrderModel(
          o.Id,
          o.ShippingAddress,
          mapper.Map&lt;IList&lt;OrderItemModel&gt;&gt;(o.Items)
      ));
  </code></pre>
  
  <p>In order to do this, I need a reference to IMappingEngine. When the mapping engine is being configured, I don't have a reference to it that can be captured in the ConvertUsing argument. A simple solution is to have a static reference to it somewhere, but I would like to avoid it.</p>
  
  <p>Is there a way to get a reference to the current IMappingEngine inside a mapping that uses ConvertUsing?</p>