Custom date/time type conversion

[lmaotrigine]

I'm the author of a (currently private) datetime library, and I would like to provide Type implementations for each database. The public API of sqlx doesn't export enough for me to implement this (column flags and charset for MySQL for example, or PgType constants).

since this is still very early stages and I foresee understandable skepticism from my own users given that there already exist well-established crates for handling these, i want to maintain these implementations myself instead of requesting the maintainers to add another feature. Is there a good way to do this?

so far, I've only had success with Postgres, because of PgType::with_name magically working; but MySqlType doesn't provide any public constructors; so I don't see a way to implement Type<MySql> for my own types. Similar woes with SQLite. Is there something I'm missing?