Linking the project

Open ios/Runner.xcodeproj in Xcode, then add $crate/$crate.xcodeproj as a subproject of the Runner project. It should look like this:

Click on the Runner root project, then go to the Build Phases tab. First, expand the Dependencies phase, and add $crate-staticlib for iOS, or $crate-cdylib for MacOS.

Then, expand the Link Binary With Libraries phase, and add lib$crate_static.a for iOS, or $crate.dylib for MacOS.