diff method
Implementation
@override
Future<providerpb.DiffResponse> diff(
ServiceCall call,
providerpb.DiffRequest request,
) async {
final olds = StructConverter.fromStruct(request.olds);
final news = StructConverter.fromStruct(request.news);
final result = await provider.diff(request.id, request.urn, olds, news);
return _buildDiffResponse(result);
}