code: func (a *Args) Sort(f func(x, y []byte) int) {
  	sort.SliceStable(a.args, func(i, j int) bool {
  		n := f(a.args[i].key, a.args[j].key)
  		if n == 0 {
  			return f(a.args[i].value, a.args[j].value) == -1
  		}
  		return n == -1
  	})
  }
docs: // Sort sorts Args by key and then value using 'f' as comparison function.
  //
  // For example args.Sort(bytes.Compare)