prepareMessage method

@override Future<Uint8List?> prepareMessage(BuildContext? context)

Will be called

Implementation

@override
Future<Uint8List?> prepareMessage(BuildContext? context) async {
  final http.Client client = _httpClient ?? http.Client();
  final http.Response response = await client.get(
    Uri.parse(url),
    headers: headers,
  );
  if (_httpClient == null) {
    client.close();
  }
  return response.bodyBytes;
}