docs: public final Long getJmsExpiration() {
          if (getHdr2().getChoiceField(JsHdr2Access.JMSEXPIRATION) == JsHdr2Access.IS_JMSEXPIRATION_EMPTY) {
              return Long.valueOf(getDerivedJmsExpiration());
          }
          else {
              return (Long) getHdr2().getField(JsHdr2Access.JMSEXPIRATION_DATA);
          }
      }