title: Anonymous IComparer implementation
body: <p>Is it possible to define an anonymous implementation of IComparer?</p>
  
  <p>I believe Java allows anonymous classes to be defined inline - does C#?</p>
  
  <p>Looking at this code I want to define a custom <code>IComparer</code> inline</p>
  
  <pre><code>public static IOrderedEnumerable&lt;TSource&gt; OrderBy&lt;TSource, TKey&gt;(
      this IEnumerable&lt;TSource&gt; source,
      Func&lt;TSource, TKey&gt; keySelector,
      IComparer&lt;TKey&gt; comparer
  )
  </code></pre>