title: Detect DJI drone power down event while RC is still powered on
body: <p>Is there a way to determine when the drone has been powered down (when the remote controller is still powered on)? For example a pilot may change the drone battery but does not power down the remote controller.</p>
  <p>I have tried using keyManager to listen to the DJIParamConnection param of DJIProductKey, DJIFlightControllerKey and DJIAirLinkKey.</p>
  <p>I also tried listening to the DJISDKManagerDelegate methods productConnected, productDisconnected, productChanged, componentConnectedWithKey, and componentDisconnectedWithKey.</p>
  <p>But none of these key values ​​or delegate methods are triggered when the drone is powered down. They only trigger when the Remote controller is also powered down.</p>
  <p>Is there another way to detect this event?</p>
  <p>Tested on M300 and Mavic Pro with iOS SDK 4.15.2</p>
  <p><strong>EDIT</strong></p>
  <p>I should have mentioned that this is running on a react native, native module. When creating a RN native module, RN puts the module on a background thread unless specified.</p>