* registry suffix is one under which Internet users can directly register names via a domain name
   * registrar, and have such registrations lawfully protected by internet-governing bodies such as
   * ICANN. Examples of registry suffixes include {@code com}, {@code co.uk}, and {@code
   * pvt.k12.wy.us}. Examples of domain names that are <i>not</i> registry suffixes include {@code
   * google.com} and {@code foo.co.uk}.
   *