Contact seemed to remain online after phone was reused
This issue arose in user testing when one of the devices was reused by another tester.
User A with device X and user B with device Y added each other as contacts. Then user C took over device Y and created a new account. User A continued to see user B as online.
This may have been caused by a Bluetooth channel remaining open between the devices, causing user A to think that a connection to user B was still open. Perhaps a subsequent connection between user A and user C either reused the channel or otherwise caused it to remain open rather than timing out, or perhaps the Bluetooth stack on device X simply doesn't time out connections in a reasonable time.
If any of those speculations are right, we should work out how to avoid relying on Bluetooth to time out the connection and time out after a reasonable time in the Bramble stack instead.
We should also check that Bluetooth connections are being disposed of properly when they're closed.