I am working with CoreBluetooth to connect to a BLE device. I want to verify if the device is already paired before performing certain actions. I followed the steps mentioned in this StackOverflow post, but I am facing an issue. Even though my device gets paired successfully, the didWriteValueFor delegate method is not being called.

Here is what I have done so far:

1. Scanning and Connecting:
   I scan for peripherals and connect to them successfully.
2. Discovering Services and Characteristics:
   I discover the services and characteristics of the connected peripheral.
3. Writing to a Characteristic:
   I attempt to write to a characteristic after ensuring that the device is paired.

Despite these steps, the didWriteValueFor method is not invoked. I’m sure the device is paired correctly. How can I reliably determine if a device is paired, and what could be causing didWriteValueFor not to be called?

class BluetoothManager: NSObject, CBCentralManagerDelegate, CBPeripheralDelegate {
    private var centralManager: CBCentralManager!
    private var connectedPeripheral: CBPeripheral?
    
    override init() {
        super.init()
        centralManager = CBCentralManager(delegate: self, queue: nil)
    }
    
    func centralManagerDidUpdateState(_ central: CBCentralManager) {
        if central.state == .poweredOn {
            centralManager.scanForPeripherals(withServices: nil, options: nil)
        }
    }
    
    func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
        connectedPeripheral = peripheral
        connectedPeripheral?.delegate = self
        centralManager.connect(peripheral, options: nil)
    }
    
    func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {
        connectedPeripheral?.discoverServices()
        peripheral.discoverServices(nil)
    }
    
    func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?) {
        guard let services = peripheral.services else { return }
        
        for service in services {
            peripheral.discoverCharacteristics(nil, for: service)
        }
    }
    
    func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
        let value = 1234
            let data = withUnsafeBytes(of: value) { Data($0) }
            for characteristic in service.characteristics!
            {
                if characteristic.properties.contains(.notify) {
                    peripheral.setNotifyValue(true, for: characteristic)
                    peripheral.writeValue(data, for: characteristic, type: .withResponse)
                }
            }
    }
    
    func peripheral(_ peripheral: CBPeripheral, didWriteValueFor characteristic: CBCharacteristic, error: Error?) {
        if let error = error {
            print("Error writing value: (error.localizedDescription)")
        } else {
            print("Successfully wrote value to (characteristic.uuid)")
        }
    }
}