/**
  * @param flag flag
  * @return a IpV4InternetTimestampOptionFlag object.
  */
 public static IpV4InternetTimestampOptionFlag register(IpV4InternetTimestampOptionFlag flag) {
   return registry.put(flag.value(), flag);
 }
 @Override
 public int compareTo(IpV4InternetTimestampOptionFlag o) {
   return value().compareTo(o.value());
 }
 static {
   registry.put(TIMESTAMPS_ONLY.value(), TIMESTAMPS_ONLY);
   registry.put(
       EACH_TIMESTAMP_PRECEDED_WITH_ADDRESS.value(), EACH_TIMESTAMP_PRECEDED_WITH_ADDRESS);
   registry.put(ADDRESS_PRESPECIFIED.value(), ADDRESS_PRESPECIFIED);
 }