Understanding a parameter in C# code
<p>IntelliSense says that the lambda parameter <code>ea</code> is a DownloadStringCompletedEvent Args. Understood, but parameter <code>s</code> is only defined as "object s". Can anyone explain the purpose of this parameter?</p>

<pre><code>WebClient client = new WebClient();

        client.DownloadStringCompleted += (s, ea) =&gt; 
                     { XDocument document = XDocument.Parse(ea.Result);
                        // ... Do something else...
                      };
</code></pre>
