title: How to minimize the costs for allocating and initializing an NSDateFormatter?
body: <p>I noticed that using an <code>NSDateFormatter</code> can be quite costly. I figured out that allocating and initializing the object already consumes a lot of time.<br>
  Further, it seems that using an <code>NSDateFormatter</code> in multiple threads increases the costs. Can there be a blocking where the threads have to wait for each other?</p>
  
  <p>I created a small test application to illustrate the problem. Please check it out.  </p>
  
  <ul>
  <li><a href="http://github.com/johnjohndoe/TestNSDateFormatter" rel="noreferrer">http://github.com/johnjohndoe/TestNSDateFormatter</a></li>
  <li>git://github.com/johnjohndoe/TestNSDateFormatter.git</li>
  </ul>
  
  <p>What is the reason for such costs and how can I improve the usage?</p>
  
  <hr>
  
  <p>17.12. - To update my observation: I do not understand why the threads run longer when processed parallel compared to when the run in serial order. The time difference only occurs when NSDateFormatter is used.</p>