Hi @jermp! When merging some sshash-related changes, it occured to us that your libraries currently require passing by non-const reference even when saving something, which, from our perspective, idiomatically should be done with const ref. We also often need to save/load stuff using a general ifstream/ofstream. Due to this I took it upon myself to

• implement a more generic version of saver/loader which can work with arbitrary streams. I made sure that this change is non-intrusive, so it will only add some functionality, but shouldn't affect your existing workflows.
• Make saving work with const references.

The later is, unfortunately, a bit more intrusive, but I strongly believe that it would be a better way to handle this. I also think that while propagating it to actual usecases require some work, it is straightforward enough, as I already did this in custom forks of pthash and sshash. If it is of interest to you, I can make separate pull requests to pthash and sshash to merge the new approach to "visit" them, and also help with the migration in your other projects, if necessary.