如何在Android Room中使用PagedListAdapter获取总查询次数

public class MyAdapter extends PagedListAdapter<MyData, MyViewHolder> {
    // ...
}

private static DiffUtil.ItemCallback<MyData> DIFF_CALLBACK = new DiffUtil.ItemCallback<MyData>() {
    @Override
    public boolean areItemsTheSame(@NonNull MyData oldItem, @NonNull MyData newItem) {
        return oldItem.getId() == newItem.getId();
    }

    @Override
    public boolean areContentsTheSame(@NonNull MyData oldItem, @NonNull MyData newItem) {
        return oldItem.equals(newItem);
    }
};

public int getTotalQueryCount() {
    PagedList<MyData> pagedList = getCurrentList();
    if (pagedList != null) {
        return pagedList.getLoadedCount();
    }
    return 0;
}

LiveData<PagedList<MyData>> myDataList = myDao.getMyDataList(new PagedList.Config.Builder()
        .setPageSize(20)
        .setPrefetchDistance(10)
        .build());

myDataList.observe(this, new Observer<PagedList<MyData>>() {
    @Override
    public void onChanged(@Nullable PagedList<MyData> myData) {
        myAdapter.submitList(myData);
    }
});

int totalQueryCount = myAdapter.getTotalQueryCount();