For low level Tor support on iOS (and a thin Objective-C wrapper), check out CPAProxy instead. We have directed our efforts toward improving CPAProxy instead of maintaining OnionKit in its current form.
We eventually plan to add higher-level UI features like a hardened WKWebView and bridge editor to OnionKit, with a dependency on CPAProxy.
The code for this project is dual licensed under the LGPLv2.1+ and MPL 2.0. The required dependencies are under terms of seperate licenses. More information is available in the LICENSE file.