iOS as Central

central.swift

// Initialize central manager, set self as delegate
centralManager = CBCentralManager(delegate: self, queue: nil, options: [CBCentralManagerOptionRestoreIdentifierKey: TraceService.CMRestoreIdentifierKey])

// Provide implementation for delegate callback methods
extension TraceService: CBCentralManagerDelegate {

    func centralManager(_ central: CBCentralManager, willRestoreState dict: [String: Any]) { ... }

    func centralManagerDidUpdateState(_ central: CBCentralManager) {
        // When .poweredOn, scan for Peripherals
    }

    func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String: Any], rssi RSSI: NSNumber) {
        // Filter Peripherals with TraceService UUID in advertisementData
        // Initiate connection to Peripheral
    }

    func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {
        peripheral.delegate = self
        peripheral.discoverServices(TraceProfile.SERVICES)
    }

    func centralManager(_ central: CBCentralManager, didFailToConnect peripheral: CBPeripheral, error: Error?) { ... }

    func centralManager(_ central: CBCentralManager, didDisconnectPeripheral peripheral: CBPeripheral, error: Error?) { ... }

}