/// <summary>
/// temporarily runs SceneTransition allowing one Scene to transition to another smoothly with custom effects.
/// </summary>
/// <param name="sceneTransition">Scene transition.</param>
public static T startSceneTransition <T>(T sceneTransition) where T : SceneTransition
{
Insist.isNull(_instance._sceneTransition, "You cannot start a new SceneTransition until the previous one has completed");
_instance._sceneTransition = sceneTransition;
return(sceneTransition);
}