code: public ViewTransitionBuilder animator(@NonNull final Animator animator) {
          addSetup(new ViewTransition.Setup() {
              @Override
              public void setupAnimation(@NonNull final TransitionControllerManager manager) {
                  Animator animator2 = animator.clone();
                  if (animator2 instanceof AnimatorSet) {
                      manager.addTransitionController(DefaultTransitionController.wrapAnimatorSet((AnimatorSet) animator2));
                  } else {
                      manager.addTransitionController(DefaultTransitionController.wrapAnimator(animator2));
                  }
              }
          });
          return self();
      }
docs: TODO Current support is rudimentary, may expand support if there are enough demand for this.
  <p>
  Converts an animator to ITransition when built, note that not all functions of Animator are supported.
  <p>
  Non-working functions: repeatMode, repeatCount, delay, duration (when in a set), Interpolator.
  <p>
  Furthermore, {@link #transitViewGroup(ViewGroupTransition)} does not work with this method.
  
  @param animator
  @return