private void acquirePage() throws IOException {
      if (isSharedPage) {
        return;
      }
      if (page == null) {
        page = (PageUnsafe)storage.pageByOffset(address, /*forWrite: */ false);
      }
      else if (!keepPageAcquiredUntilDispose) {
        boolean acquiredSuccessfully = page.tryAcquire(this);
        if (!acquiredSuccessfully) {
          page = (PageUnsafe)storage.pageByOffset(address, /*forWrite: */ false);
        }
      }//else: if(keepPageAcquiredUntilDispose) -> page must be already acquired, if !null
    }
private void acquirePage()