title: how to use process.hrtime to get execution time of async function
body: <p>I am triing to get execution time of async function. Seemingly I can use <a href="http://nodejs.org/docs/v0.8.0/api/all.html#all_process_hrtime">process.hrtime</a> for this. I created simple example:</p>
  
  <pre><code>console.log("starting");
  var start = process.hrtime();
  console.log("start");
  console.log(start);
  
  setTimeout(function(){
      console.log("HELLO");
      var end = process.hrtime();
      console.log("end");
      console.log(end);
  }, 1000);
  </code></pre>
  
  <p>It outputs</p>
  
  <pre><code>starting
  start
  [ 131806, 731009597 ]
  HELLO
  end
  [ 131807, 738212296 ]
  </code></pre>
  
  <p>But I don't understand where is exectuion time in miliseconds? I expect to get 1000 ms in this example.</p>