非同期動作のコルーチンで使用します。
You can yield until asynchronous operation continues, or manually check whether it's done
(isDone) or progress (progress).
See Also: SceneManager.LoadSceneAsync, AssetBundle.LoadAssetAsync, Resources.LoadAsync.
| allowSceneActivation | シーンが準備完了となったタイミングですぐにシーンが有効化されることを許可します。 |
| isDone | 動作が終了したか確認します（読み取り専用） |
| priority | 非同期で読み込む際の優先順位を設定します。 |
| progress | 進捗状況を表示します（読み取り専用） |
| completed | Event that is invoked upon operation completion. An event handler that is registered in the same frame as the call that creates it will be invoked next frame, even if the operation is able to complete synchronously. If a handler is registered after the operation has completed and has already invoked the complete event, the handler will be called synchronously. |