private Handler mHandler = new Handler();

/**
     * Adds to the cache WatchLater List a {@link WatchLaterItem}
     *
     * @param itemToAdd {@link WatchLaterItem}
     */
    private void addItemToWatchLaterList(WatchLaterItem itemToAdd) {
        final Map<String, WatchLaterItem> itemsByEditorialVersionIdMap = new HashMap<>();
        final List<WatchLaterItem> watchLaterItems = new ArrayList<>();
        watchLaterItems.addAll(mRetrievedWatchLaterList);
        itemsByEditorialVersionIdMap.putAll(mItemsByEditorialVersionIdMap);

        if (itemToAdd.href == null || itemToAdd.href.isEmpty()) {
            itemToAdd.href = generateRandomHRef();
        }
        final String editorialVersionId = itemToAdd.editorialVersionId;
        itemsByEditorialVersionIdMap.put(editorialVersionId, itemToAdd);
        watchLaterItems.add(itemToAdd);
        // Assign in UI Thread
        mHandler.post(new Runnable() {
            @Override
            public void run() {
                synchronized (WatchLaterListManager.this) {
                    mRetrievedWatchLaterList.clear();
                    mRetrievedWatchLaterList.addAll(watchLaterItems);
                    mItemsByEditorialVersionIdMap.clear();
                    mItemsByEditorialVersionIdMap.putAll(itemsByEditorialVersionIdMap);
                    Log.d(TAG, "Add to WatchLater list cache: " + editorialVersionId);
                }
            }
        });
    }