title: Swift get difference between two dates in GMT
body: <p>I recently noticed strange behaviour trying to find the difference between two dates (in seconds). </p>
  
  <p>I have a datestring that is in GMT time:</p>
  
  <pre><code>2016-01-07 01:09:47.289000
  </code></pre>
  
  <p>I want to find how many seconds since that time NOW.</p>
  
  <p>But I notice that when I use NSDate() I get the time of my local time, not GMT time. </p>
  
  <p>How would I go about doing this?</p>