code: func (s Traces) String() string {
  	if len(s) == 0 {
  		return ""
  	}
  	out := make([]string, len(s))
  	for i, t := range s {
  		out[i] = fmt.Sprintf("\t%v:%v %v", t.Path, t.Line, t.Func)
  	}
  	return strings.Join(out, "\n")
  }
docs: // String returns debug-friendly representaton of trace stack