title: When does a background task get aborted because of "ResourceRevocation", and how do I prevent it?
body: <p>I'm working on an UWP (Win10) app that needs to maintain a persistent Rfcomm connection to a bluetooth accessory.</p>
  
  <p>Seemingly at random, the OS decides to kill off the background task. The cancellation reason is "ResourceRevocation".</p>
  
  <p>What are the conditions for a ResourceRevocation to occur, and how do I prevent it?</p>
  
  <p>I've tried switching background task type (RfcommTrigger / DeviceUseTrigger), but they all get killed by the OS.</p>