code: public static InstanceId of(ZoneId zoneId, String instance) {
      return new InstanceId(zoneId.getProject(), zoneId.getZone(), instance);
    }
docs: Returns an instance identity given the zone identity and the instance name. The instance name
  must be 1-63 characters long and comply with RFC1035. Specifically, the name must match the
  regular expression {@code [a-z]([-a-z0-9]*[a-z0-9])?} which means the first character must be a
  lowercase letter, and all following characters must be a dash, lowercase letter, or digit,
  except the last character, which cannot be a dash.
  
  @see <a href="https://www.ietf.org/rfc/rfc1035.txt">RFC1035</a>