In the great tradition of TPP, this is a win. We've gone through
the test driven development, and there is so much *learning* here:
- tokio::test NEEDS the threaded_schedular feature to report errors correctly
- thiserror can't do enum variants the way I expected
- Different error types for different returns is not kosher
- Serde's configuration NEEDS a type, such as JSON, to work,
- Rust has include_str!(), to embed text in a Rust program from an external source
- SQLX is still a pain, but it's managable.