title: What, exactly, is a BLE connected device on iOS?
body: <p>The <code>CBCentralManager retrieveConnectedPeripherals</code> method says it gets "the list of the peripherals currently connected to the system." The definition of system is a bit ambiguous here. </p>
  
  <p>Does this mean I get a list of peripherals connected to my app, or a list of peripherals connected to <em>any</em> app? </p>
  
  <p>If I can get peripherals connected to another app, does this also mean multiple apps can connect to the same peripheral? </p>
  
  <p>Can this only happen if the app is in the foreground, or do I need to allow for the possibility that a background app is sending commands to a peripheral I think my app owns?</p>