code: public static RegionForwardingRuleId of(String project, String region, String rule) {
      return new RegionForwardingRuleId(project, region, rule);
    }
docs: Returns a region forwarding rule identity given project, region and rule names. The forwarding
  rule 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>