set
Registers the listener told whenever a headset or Bluetooth device is plugged in or removed, or the selected route changes.
It fires once straight away with the current selection and list, so a picker built in the callback needs no separate first read. Replaces any previous listener; null removes it. The registration is process-wide and survives leave.
Parameters
listener
receives (selected, available); selected is null only when no audio route is available, which is always the case before VideoSDK.initialize.