routeguide_service_ss.bal

service "RouteGuide" on new grpc:Listener(8980) {

    remote function ListFeatures(Rectangle rectangle) returns stream<Feature, grpc:Error?>|error {
        int left = int:min(rectangle.lo.longitude, rectangle.hi.longitude);
        int right = int:max(rectangle.lo.longitude, rectangle.hi.longitude);
        int top = int:max(rectangle.lo.latitude, rectangle.hi.latitude);
        int bottom = int:min(rectangle.lo.latitude, rectangle.hi.latitude);

        Feature[] selectedFeatures = from var feature in FEATURES
            where feature.name != ""
            where feature.location.longitude >= left
            where feature.location.longitude <= right
            where feature.location.latitude >= bottom
            where feature.location.latitude <= top
            select feature;

        return selectedFeatures.toStream();
    }
  ...
}