Open Layers 3 detect if WMS feed hasn't worked
<p>I have an Open Layers 3 implementation which reads data from a WMS data feed.</p>

<p>I've noticed that if the WMS data feed goes down I don't get any errors on the browser side, it just doesn't receive any layers.</p>

<p>Is there a way in Open Layers 3 to detect if a WMS call returns nothing?</p>

<p>I have tried the experimental function <code>getState()</code>, but this always returns <strong>ready</strong> even on bad WMS calls.</p>