title: How do we use the facebook React addons Perf class?
body: <p>Trying a very simple thing, and am getting errors "TypeError: Cannot read property 'counts' of undefined"</p>
  
  <p>Here's the hello world example code.</p>
  
  <p><a href="https://gist.github.com/joshuacalloway/ae5b184c485956314d1c">https://gist.github.com/joshuacalloway/ae5b184c485956314d1c</a></p>