MainActor for ViewModel class

MainActorForClass.swift

@MainActor
class UserViewModel: ObservableObject {
    @Published private(set) var userDetails = UserDetails()
    
    func loadUserDetails() {
        Task {
            do {
                userDetails = try await fetchUserData()
            } catch {
                showError(error)
            }
        }
    }
    
    func fetchUserData() async throws -> UserDetails {
        try await withCheckedThrowingContinuation { continuation in
            fetchUserData { result in
                switch result {
                case .success(let user):
                    continuation.resume(returning: user)
                case .failure(let error):
                    continuation.resume(throwing: error)
                }
            }
        }
    }
    
    func showError(_ error: Error) {
        // handle errors
    }
    
    func fetchUserData(_ result: @escaping(Result<UserDetails, Error>)-> ()) {
        // your async operation ...
    }
}