I currently have a custom Java / c++ application running on Ubuntu 20.04 that records an NDI video device as soon as it is presented on the network via mDNS. I'd also like to programmatically stop recording this video stream once the device is no longer connected to the network.
The problem is that the mDNS record for this device is cached locally and does not 'disappear' from the network once the physical device is turned off.
I've looked at the avahi-daemon.conf and avahi-utils, but haven't been able to find an option to clear/refresh the device registry in an ad-hoc fashion.
Does anyone have any suggestions for how I could immediately poll the network to see if this mDNS device is no longer present?