How to do certificate pinning with chopper client

Question

I'm developing an application using ChopperClient. To improve application security I want to do certificate pinning by using http_certificate_pinning library.

What I've tried: I try using HttpCertificatePinning.check as suggested in the library's official guide. The serverURL is my mock api url. When I run the application, the application crashed and exited. When I change the url to https://www.google.com/ the application is not crash and the result is returned as false.

Does anyone have experience using Chopper with this library? How should I do certificate pinning with this library?

Future<bool> myCustomImplementation(String url, Map<String, String> headers,
  List<String> allowedSHAFingerprints) async {
try {
  final String secure = await HttpCertificatePinning.check(
      serverURL: url, //mock api url
      headerHttp: headers, //mock headers
      sha: SHA.SHA256,
      allowedSHAFingerprints: allowedSHAFingerprints, //mock fingerprints
      timeout: 100);

  if (secure.contains("CONNECTION_SECURE")) {
    return true;
  } else {
    return false;
  }
} catch (e) {
  return false;
}

}