title: UICollectionView contentOffset changes when keyboard appears
body: <p>I am trying to implement <code>PullDown To Search</code> feature in my app. To implement this i just modified bit <a href="https://github.com/enormego/EGOTableViewPullRefresh" rel="noreferrer">EGOTableViewPullRefresh
  </a> it is working good except an issue.</p>
  
  <p><strong>Issue</strong></p>
  
  <p>When user opens the application following screen shall appear. initially the <code>UICollectionView's</code> <code>contentoffset</code> shall be <code>(0,0)</code>
  <img src="https://i.stack.imgur.com/JsjCy.png" alt="enter image description here"></p>
  
  <p>If user pulls down the collection view the following screen shall appear at this point the <code>contentoffset</code> of <code>UICollectionView</code> shall be <code>(0,-60)</code>
  <img src="https://i.stack.imgur.com/AXEns.png" alt="enter image description here"></p>
  
  <p>User can search by entering their text in the above screen. My issue is occurring in this screen as soon as user taps the <code>UITextField</code> to enter text <code>contentoffset</code> of <code>UICollectionView</code> changes <code>(0,-60)</code> to <code>(0,-110)</code> and UI loosks like bellow screen. I am not sure why this change occurs can you please guide me to resolve this?</p>
  
  <p><img src="https://i.stack.imgur.com/qGm8h.png" alt="enter image description here"></p>