private boolean setLongFieldIfChanged(int fieldRelativeOffset,
                                          long newValue) {
      int fieldOffsetInPage = recordOffsetInPage + fieldRelativeOffset;
      long oldValue = (long)LONG_HANDLE.getVolatile(pageBuffer, fieldOffsetInPage);
      if (oldValue != newValue) {
        setLongVolatile(pageBuffer, fieldOffsetInPage, newValue);
        return true;
      }
      return false;
    }
private boolean setLongFieldIfChanged(int fieldRelativeOffset,
                                          long newValue)