title: QLowEnergyController: How to detect connection closed by peer?
body: <p>I designed an Android application using Qt. I use <code>QLowEnergyController</code> to work with a remote BLE device.</p>
  
  <p>When I programmatically ask to disconnect the device (calling myself <code>QLowEnergyController::disconnectFromDevice()</code>), the signal <code>QLowEnergyController::disconnected()</code> is emited. Fine.</p>
  
  <p>Now, if I turn off the BLE device (like if peer closed the connection), <code>QLowEnergyController::disconnected()</code> is not emited. </p>
  
  <ul>
  <li>If I wait 15 seconds, then <code>QLowEnergyController::disconnected()</code> is emitted.</li>
  <li>Or, if I try to access the device (reading a descriptor for instance), this fails and instantely <code>QLowEnergyController::disconnected()</code> is emitted.</li>
  </ul>
  
  <p>Is there a way to be notified earlier that connection is lost (closed by remote device or lost because it becomes unreachable, like being too far)?</p>