title: Is there any reason to not use sleep in a Grand Central Dispatch queue?
body: <p>I would like to make a queue wait for a short period while it is looping. I am considering my options and was testing out suspending a resuming a queue but that seems to require several moving parts. So I am considering using sleep or usleep instead. That is more of a general threading function and would like to know if I should avoid using sleep and instead stick with GCD options to make a queue pause.</p>
  
  <p>I found one related question but that answer shows that he was just missing an include. Are there any concerns with mixing sleep calls in with GCD queues?</p>
  
  <p><a href="https://stackoverflow.com/questions/4668634/iphone-is-it-ok-to-use-usleep-on-a-secondary-thread-on-grand-central-dispatch">iphone - is it ok to use usleep on a secondary thread on Grand Central Dispatch?</a></p>