type 'Future' is not a subtype of type 'FutureOr' in type cast while trying to retrive bluetooth state in flutter

Question

See error screenshot

I'm trying to monitor the state of the bluetooth device. For example a users bluetooth is turned on before entering the app. I want the bluetooth swtich to be turned on in the app. I am using GetX for state management

BluetoothState bluetoothState = BluetoothState.UNKNOWN;
 Future<void> enableBluetooth() async {
// Retrieving the current Bluetooth state
      bluetoothState = await 
FlutterBluetoothSerial.instance.state.;
// If the bluetooth is off, then turn it on first
// and then retrieve the devices that are paired.
if (bluetoothState == BluetoothState.STATE_OFF) {
  await FlutterBluetoothSerial.instance.requestEnable();
  await getPairedDevices();
  return true;
} else {
  await getPairedDevices();
}
return false;

}