code: func (t *Trace) String() string {
  	dir, file := filepath.Split(t.Path)
  	dirs := strings.Split(filepath.ToSlash(filepath.Clean(dir)), "/")
  	if len(dirs) != 0 {
  		file = filepath.Join(dirs[len(dirs)-1], file)
  	}
  	return fmt.Sprintf("%v:%v", file, t.Line)
  }
docs: // String returns debug-friendly representation of this trace