title: Uber API => ETA is not updated in sandbox mode (accepted)
body: <p>Well, I am making android and iOS app and integrating the Uber Api for taxi request. I am using the Uber-API in sand-box mode</p>
  
  <p>I want to impelement this</p>
  
  <p><em>If in status ACCEPTED and ETA &lt;=2 min: 
  show message Your Personal Driver will arrive in less than 2 minutes.</em></p>
  
  <p><em>If status ACCEPTED and ETA == 0: 
  Show message Your Personal Driver has arrived.</em></p>
  
  <p><strong>Problem</strong></p>
  
  <p>I am using the sandbox mode, the ETA is not changing.</p>
  
  <p>Here is the out put </p>
  
  <pre><code>{
  driver =     {
      name = John;
      "phone_number" = "(555)555-5555";
      "picture_url" = "https://d1a3f4spazzrp4.cloudfront.net/uberex-sandbox/images/driver.jpg";
      rating = "4.9";
  };
  eta = 7; // Note: this ETA, This always remains 7 not changing
  location =     {
      bearing = "-122";
      latitude = "47.36758";
      longitude = "8.54552";
  };
  "request_id" = "40edd821-e87a-4401-866a-126e15e1dce1";
  status = accepted;
  "surge_multiplier" = 1;
  vehicle =     {
      "license_plate" = "UBER-PLATE";
      make = Toyota;
      model = Prius;
      "picture_url" = "https://d1a3f4spazzrp4.cloudfront.net/uberex-sandbox/images/prius.jpg";
  };}
  </code></pre>
  
  <p><strong>Uber App</strong></p>
  
  <p>In the uber app the arriving ETA is accurate
  10min
  then 9,8,7...1,0</p>
  
  <p>is this a sandbox restriciton or an uber-api Bug.?</p>