title: Code Analysis rule not triggered for a likely memory leak
body: <p>The type <code>HttpResponseMessage</code> is an IDisposable: <code>public class HttpResponseMessage : IDisposable</code></p>
  <p>I intentionally enabled <code>CA2000</code> in my Solution Explorer to detect places in my code where I forgot to explicitly dispose of things.</p>
  <p>Given this simple method below, I was expecting the Code Analysis engine to generate a <code>CA2000</code> response, but it did not. Shouldn't <code>response</code> be disposed?</p>
  <pre><code>private async Task&lt;T&gt; GetAsync&lt;T&gt;(string url)
  {
      // GetSomeHttpResponseAsync is a custom extension method if that helps.
      HttpResponseMessage response = await myHttpClient.GetSomeHttpResponseAsync(url);
      return await DeserializeJsonAndHandleClientError&lt;T&gt;(response);
  }
  </code></pre>