code: private final byte getFlags() {
          if (!gotFlags) {
              flags = ((Byte) getHdr2().getField(JsHdr2Access.FLAGS)).byteValue();
              gotFlags = true;
          }
          return flags;
      }
docs: Get the byte value of the FLAGS field from the cached variable or directly
  from the message.
  
  @return byte The value of the (possibly cached) FLAGS field.