updateCharacteristicValue method
Implementation
void updateCharacteristicValue(
  String deviceId,
  String characteristicId,
  Uint8List value,
) {
  characteristicId = BleUuidParser.string(characteristicId);
  _valueStreamController.add((
    deviceId: deviceId,
    characteristicId: characteristicId,
    value: value,
  ));
  try {
    onValueChange?.call(deviceId, characteristicId, value);
  } catch (_) {}
}