Relevant functions: - [`proj_as_projjson`](https://proj.org/en/9.3/development/reference/functions.html#c.proj_as_projjson) - [`proj_as_wkt`](https://proj.org/en/9.3/development/reference/functions.html#c.proj_as_wkt) Would the right place to put these be as methods on the `Proj` struct?