title: Why is NSFastEnumeration fast?
body: <p>Does anybody know whether <a href="http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/NSFastEnumeration_protocol/Reference/NSFastEnumeration.html" rel="noreferrer"><code>NSFastEnumeration</code></a> is really faster (as in run-time performance) than using <a href="http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSEnumerator_Class/Reference/Reference.html" rel="noreferrer"><code>NSEnumerator</code></a> or (for arrays) using an integer counter and loop through the elements? </p>
  
  <p>If it is indeed faster, how does it achieve that speed?</p>
  
  <p>Or perhaps the "fast" actually refers to faster in <em>writing</em> the iteration code?</p>
  
  <p>Thanks in advance.</p>