inline HeapWord* par_allocate_no_bot_updates(size_t word_size) {

  {- -------------------------------------------
  (1) (assert)
      ---------------------------------------- -}

        assert(is_young(), "we can only skip BOT updates on young regions");

  {- -------------------------------------------
  (1) ContiguousSpace::par_allocate() で確保を行い, 結果をリターン.
      ---------------------------------------- -}

        return ContiguousSpace::par_allocate(word_size);
      }