docs: public void setTransition(@NonNull Scene fromScene, @NonNull Scene toScene, @Nullable Transition transition) {
          ArrayMap<Scene, Transition> sceneTransitionMap = mScenePairTransitions.get(toScene);
          if (sceneTransitionMap == null) {
              sceneTransitionMap = new ArrayMap<Scene, Transition>();
              mScenePairTransitions.put(toScene, sceneTransitionMap);
          }
          sceneTransitionMap.put(fromScene, transition);
      }