Turf development is funded by Mapbox. If you need more Geo functionality than that provided by https://github.com/georust/rust-geo (I'm one of the developers), contributions are actively encouraged, and we're happy to mentor people. Alternatively, feel free to pay for some dev time if you need something specific (e.g. OpenCage paid to have their geocoder included in https://github.com/georust/rust-geocoding, dual-licensed as Apache / MIT).