title: Optional Arguments or Named Arguments initialized to null? C#
body: <p>I came across an example similar to this:</p>
  
  <pre><code>public Dictionary&lt;string, object&gt; generate(
    string elementId,
    Dictionary&lt;string, object&gt; additionalAttributes = null)
  {
  .... method body
  }
  </code></pre>
  
  <p>Why would the dictionary passed as parameter be initiated to null? I haven't seen such construct. Does it have to do something with an optional parameter?</p>