title: Memory issue with CFString
body: <p>When I turn off the WiFi during a series of AFNetworking server requests, I am getting increase of memory without any reason. I have provided the memory profile given by instruments. Why is this increasing while not doing anything? How can I get rid of this?</p>
  
  <p><img src="https://i.stack.imgur.com/ExAqI.png" alt="The screen shot of zombie instrument result"></p>