渲染管线管理器。
| currentPipeline | Returns the active RenderPipeline. |
| beginCameraRendering | Delegate that you can use to invoke custom code before Unity renders an individual Camera. |
| beginFrameRendering | Delegate that you can use to invoke custom code at the start of RenderPipeline.Render. |
| endCameraRendering | Delegate that you can use to invoke custom code after Unity renders an individual Camera. |
| endFrameRendering | Delegate that you can use to invoke custom code at the end of RenderPipeline.Render. |