There is nothing stopping you from doing it yourself. The Sqlite FAQ[1] even has an entry on it.

Two things holding this back: 1. code being inside our outside sqlite would not be much different. 2. the amount of additional test code would be humongous for an operation of that level of complexity.

So, just do it yourself. It's not that hard.

[1]: https://www.sqlite.org/faq.html#q11