code: func GetElapsedTime(o dhcp6.Options) (ElapsedTime, error) {
  	v, err := o.GetOne(dhcp6.OptionElapsedTime)
  	if err != nil {
  		return 0, err
  	}
  
  	var t ElapsedTime
  	err = (&t).UnmarshalBinary(v)
  	return t, err
  }
docs: // GetElapsedTime returns the Elapsed Time Option value, as described in RFC
  // 3315, Section 22.9.
  //
  // The time.Duration returned reports the time elapsed during a DHCP
  // transaction, as reported by a client.