KMP-Swift: Return a Flow from Swift

KotlinSide.kt

interface SomeRepo {
  val selectedProfileFlow: Flow<String>
}

// iosMain
interface ProfileObserver {
  fun startObserving(onChange: (String) -> Unit)
  fun stopObserving()
}

// iosMain

class IosRepo(private val profileObserver: ProfileObserver): SomeRepo {
  override val selectedProfileFlow: Flow<String> get() = callbackFlow {
    profileObserver.startObserving { profile ->
      trySend(profile)
    }
    awaitClose {
      profileObserver.stopObserving()
    }
  }
}

SwiftSide.swift

// Example on iOS that uses a Combine Publisher. You could implement it in other ways like for await or delegates or callbacks
class IosProfileObserver: ProfileObserver {
  private var cancellables: Set<AnyCancellable>
  
  func startObserving(onChange: @escaping (String) -> Void) {
    profilePublisher.sink { profile in
      onChange(profile)
    }.storeIn(&cancellables)
  }
  
  func stopObserving() {
    cancellables.forEach { $0.cancel() }
  }
}