code: @NonNull
      public static Animator[] concatAnimators(@NonNull final Animator[] childAnimators, @NonNull final Animator[] animators, @NonNull final Animator alphaAnimator) {
          Animator[] allAnimators = new Animator[childAnimators.length + animators.length + 1];
          int i;
  
          for (i = 0; i < childAnimators.length; ++i) {
              allAnimators[i] = childAnimators[i];
          }
  
          for (Animator animator : animators) {
              allAnimators[i] = animator;
              ++i;
          }
  
          allAnimators[allAnimators.length - 1] = alphaAnimator;
          return allAnimators;
      }
docs: Merges given Animators into one array.