title: How to unzip a .zip file on iOS?
body: <p>After StoreKit downloads the IAP content package it returns an NSURL to me which looks like this:</p>
  
  <blockquote>
    <p>file://localhost/private/var/mobile/Applications/45EF2B3A-3CAB-5A44-4B4A-631A122A4299/Library/Caches/BA32BC55-55DD-3AA4-B4AC-C2A456622229.zip/</p>
  </blockquote>
  
  <p>Despite all sources I found claiming that StoreKit unzips the content package once downloaded, it hands me over a ZIP. This ZIP probably contains the file structure of the content package. But how do I unzip this?</p>