virtual void task() {

  {- -------------------------------------------
  (1) VM_EnableBiasedLocking により biased locking を有効化する.
      ---------------------------------------- -}

        // Use async VM operation to avoid blocking the Watcher thread.
        // VM Thread will free C heap storage.
        VM_EnableBiasedLocking *op = new VM_EnableBiasedLocking(true);
        VMThread::execute(op);

  {- -------------------------------------------
  (1) biased locking の有効化処理を行うのは1回でいいので, 終わったら自分自身を消去する.
      ---------------------------------------- -}

        // Reclaim our storage and disenroll ourself
        delete this;
      }