docs: public HeaderValues fiCurrent(long cookie) {
          try {
              final Object[] table = this.table;
              int ri = (int) (cookie >> 32);
              int ci = (int) cookie;
              final Object item = table[ri];
              if (item instanceof HeaderValues[]) {
                  return ((HeaderValues[])item)[ci];
              } else if (ci == 0) {
                  return (HeaderValues) item;
              } else {
                  throw new NoSuchElementException();
              }
          } catch (RuntimeException e) {
              throw new NoSuchElementException();
          }
      }