How can I be notified of a bluetooth connection when the iOS app is backgrounded in Xamarin?

We need our app to receive notifications from the OS when the connects or disconnects from a bluetooth audio device (specifically, the one in their car).

The app gets notified when the BT device initially connects, but it then immediately seems to disconnect and logs the error:

BTCentralManager::DisconnectedPeripheral > SoundCore mini(ATT) ERROR Error Domain=CBErrorDomain Code=7 "The specified device has disconnected from us."

...and the "DisconnectedPeripheral" event is never actually fired.

We're unsure how to simply receive connect and disconnect events while the app is backgrounded.

Do we need to connect the peripheral with the central manager? We only need to know if the audio device is connected or not - we don't need to interact with it in any way.

The events never call a second time from the background, after getting the disconnect peripheral. Presumably because of the error message we are receiving.

Sample code below:

public class BTCentralManager : CBCentralManagerDelegate
{
    public CBCentralManager centralManager;
    public static CBPeripheral peripheral;

    public BTCentralManager()
    {
        System.Diagnostics.Debug.WriteLine("BTCentralManager::Constructor > ");

        centralManager = new CBCentralManager(this, new DispatchQueue("myqueue"),
            new CBCentralInitOptions { ShowPowerAlert = true, RestoreIdentifier = "myRestoreIdentifier" });

        NSUuid[] arr = { new NSUuid("7e9002be-547f-42bc-8d56-209736f70aa2") }; //Sound core mini          

        var devices = centralmanager.retrieveperipheralswithidentifiers(arr);
        peripheral = devices.firstordefault();

        //is the only way to trigger the events, we need to first connect the peripheral to central manager???
       centralManager.connectPeripheral(peripheral, new PeripheralConnectionOptions
       {
           NotifyOnConnection = true,
           NotifyOnDisconnection = true,
           NotifyOnNotification = true
       });

    }

    //Always is triggered inclusive in background
    public override void UpdatedState(CBCentralManager central)
    {
        System.Diagnostics.Debug.WriteLine("BTCentralManager::UpdatedState > " + central.State.ToString());
    }

    //Only is triggered when the device is first time connected  ( Inclusive in background)
    public override void ConnectedPeripheral(CBCentralManager central, CBPeripheral peripheral)
    {
        System.Diagnostics.Debug.WriteLine("BTCentralManager::ConnectedPeripheral > " + peripheral.Name);

        //After the connect made successfully I receive this error, and never connect again to the device
        //Error Domain=CBErrorDomain Code=7 "The specified device has disconnected from us."
    }

    public override void DisconnectedPeripheral(CBCentralManager central, CBPeripheral peripheral, NSError error)
    {
        System.Diagnostics.Debug.WriteLine("BTCentralManager::DisconnectedPeripheral > " + peripheral.Name + " ERROR>" + error.Description);
    }

    public override void DiscoveredPeripheral(CBCentralManager central, CBPeripheral peripheral, NSDictionary advertisementData, NSNumber RSSI)
    {
        System.Diagnostics.Debug.WriteLine("BTCentralManager::DiscoveredPeripheral > " + peripheral.Name);
        //   base.DiscoveredPeripheral(central, peripheral, advertisementData, RSSI);
    }
}