When switching to a new transmitter, stop restoring the first one

[loudnate]

BluetoothManager only assumes there's one peripheral we care about, which isn't true as we continue to restore the original one.

In the interest of reusing BluetoothManager in other use cases and projects, let's always ask the delegate (in this case, the Transmitter class) for permission before connecting.

[dennisgove]

Will this result in asking the user for permission?

[loudnate]

The user has already provided a TransmitterID, but we're not using to differentiate peripherals during scan or restore.

[dennisgove]

Ok. I was wondering if asking the transmitter for permission would result in having to ask the user permission for the app to access Bluetooth. I wouldn't want to have to repeat that popup request to the user.

[loudnate]

Oh, sorry, you definitely have to do that. It's a new peripheral.

[loudnate]

that is, if you're not running in "passive mode", in which case you've already responded to that dialog in the Dexcom app.

[dennisgove]

I see. What's the use case for " continue to restore the original one"?

I only ever use in passive mode so suspect I'm missing something here.

[loudnate]

CoreBluetooth supports something called State Restoration which makes it quicker to re-launch your app in response to bluetooth events, if it was closed for reasons like memory pressure. When the app relaunches and state is restored, you receive a list of all previously connected (or connection-pending) peripherals from the time the app was terminated.

So my first G5 Transmitter went dead yesterday, and I opened a new one, but the library wasn't accounting for having more than one peripheral in its restoration array, and would choose the last one each time. This meant spotty readings until I realized the issue. PR incoming...

[loudnate]

@dennisgove Have you updated to the latest version of the Dexcom G5 app?

[dennisgove]

I updated to 1.0.19 earlier today and haven't seen any issues in glucose-badge, but I haven't been watching consistently.

[loudnate]

I filed #10 to track. I'm seeing successful updates happening only every 30 minutes or so in my app, but the dex app seems to be getting every reading.