code: func hasUUIDPrefix(s string) bool {
  	if len(s) < 36 {
  		return false
  	}
  	var count int
  	for i, r := range s {
  		// should not be multi byte char
  		if count != i {
  			return false
  		}
  		switch count {
  		case 8, 13, 18, 23:
  			if r != '-' {
  				return false
  			}
  		default:
  			if !isHex(r) {
  				return false
  			}
  		}
  		if count == 35 {
  			return true
  		}
  		count += 1
  	}
  
  	// should not run here
  	return false
  }
docs: // UUID's 8, 13, 23, 18 is '-'
  // e.g. 9E242A66-4EA6-4323-AD5C-66A76F4472FE