| 123456789101112131415161718192021222324 | package trackingimport (	"time"	"github.com/go-kit/kit/log")type loggingService struct {	logger log.Logger	next   Service}// NewLoggingService returns a new instance of a logging Service.func NewLoggingService(logger log.Logger, s Service) Service {	return &loggingService{logger, s}}func (s *loggingService) Track(id string) (c Cargo, err error) {	defer func(begin time.Time) {		s.logger.Log("method", "track", "tracking_id", id, "took", time.Since(begin), "err", err)	}(time.Now())	return s.next.Track(id)}
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