A Worker could not be started immediately because other documents in the same origin are already using the maximum number of workers. The Worker is now queued and will be started after some of the other workers have completed.
Worker をすぐに開始できませんでした。同一生成元の他のドキュメントがすでに worker の数を上限まで使用しています。Worker をキューに追加し、他の worker の完了後に開始します。