void ThreadLocalAllocBuffer::initialize_statistics() {

  {- -------------------------------------------
  (1) 各フィールドを 0 に初期化するだけ.
      ---------------------------------------- -}

        _number_of_refills = 0;
        _fast_refill_waste = 0;
        _slow_refill_waste = 0;
        _gc_waste          = 0;
        _slow_allocations  = 0;
    }