docs: @NonNull
      public AsyncTaskTokenController attachAsyncTaskTokenController(@NonNull Button button) {
          if (mAsyncTaskController == null) {
              mAsyncTaskController = new AsyncTaskTokenController(
                      button,
                      mCardInputWidget,
                      mContext,
                      mErrorDialogHandler,
                      mListViewController,
                      mProgressDialogController);
          }
          return mAsyncTaskController;
      }