ViewState.swift

final class ViewPresenter {
    init(dataObserver: DataObserver) {
        self.viewState = ViewState(dataObserver: dataObserver)
    }

    let viewState: ViewState
}

@MainActor final class ViewState: ObservableObject {
    let dataObserver: DataObserver

    nonisolated init(dataObserver: DataObserver) {
        // Main actor-isolated property 'dataObserver' can not be mutated 
        // from a non-isolated context; this is an error in Swift 6
        self.dataObserver = dataObserver
    }

    @Published private(set) var status: Status = .loading
    @Published private(set) var contacts: [Contact] = []
}