title: String comparison: InvariantCultureIgnoreCase vs OrdinalIgnoreCase?
body: <p>Which would be better code:</p>
  
  <pre><code>int index = fileName.LastIndexOf(".", StringComparison.InvariantCultureIgnoreCase);
  </code></pre>
  
  <p>or</p>
  
  <pre><code>int index = fileName.LastIndexOf(".", StringComparison.OrdinalIgnoreCase);
  </code></pre>