Render Pipeline manager.
| currentPipeline | Returns the instance of the currently used Render Pipeline. |
| beginCameraRendering | Call that should be issued by an SRP when the SRP begins to render a Camera so that other systems can inject per camera render logic. |
| beginFrameRendering | Call that should be issued by an SRP when the SRP begins to render so that other systems can inject 'pre render' logic. |
| endCameraRendering | Call that should be issued by an SRP after the SRP ends to render a Camera so that other systems can inject per camera render logic. |
| endFrameRendering | Call that should be issued by an SRP when the SRP ends to render so that other systems can inject 'post render' logic. |