addCharacteristic method
      
Future<String> 
addCharacteristic(
    
- String serviceId,
- String characteristicUuid,
- CharacteristicProperties properties
Adds a characteristic with |characteristicUuid| and |properties| to the service represented by |serviceId|. Returns: An identifier that uniquely represents this characteristic.
Implementation
Future<String> addCharacteristic(
  String serviceId,
  String characteristicUuid,
  CharacteristicProperties properties,
) async {
  var result = await _client.send('BluetoothEmulation.addCharacteristic', {
    'serviceId': serviceId,
    'characteristicUuid': characteristicUuid,
    'properties': properties,
  });
  return result['characteristicId'] as String;
}