getExternalJson method
Implementation
Future<OffChainMetadata> getExternalJson() async {
final response = await http.get(Uri.parse(uri));
if (response.statusCode != 200) {
throw HttpException(response.statusCode, response.body);
}
return OffChainMetadata.fromJson(
json.decode(response.body) as Map<String, dynamic>,
);
}