Can we process std::vector<string> with the strigi header?

This might be too much to ask, but is there a way to process `std::vector` using functions from stringi? I want to do this because we cannot pass `CharacterVector` to child processes of RcppParallel (Intel TBB).

More specifically, I want to apply `stri_sub()` to a CharacterVectors with millions of elements with different `from` and `to` values, and combined the results.