title: Using grequests to send a pool of requests, how can I get the response time of each individual request?
body: <p>I am using the grequests python library to send GET requests asynchronously to our server.</p>
  
  <p>I cant figure out how to get the server response time for each individual request within the pool of requests being sent out?</p>
  
  <pre><code>unsentrequests=(grequests.get(u) for u in self.urls) # make a pool of requests
  responses=grequests.map(unsentrequests) # send the requests asynchronously
  </code></pre>
  
  <p>To get the start time of a request-response pair I could do the following:</p>
  
  <pre><code>grequests.get(u,headers={'start':time.time())
  print responses[0].request.headers['start_time']
  </code></pre>
  
  <p>But how can I grap the time that the response was received at?</p>