struct NetworkError: Error {}

func fetchUserName(id: Int) async throws -> String {
    // Simulates a network call
    try await Task.sleep(nanoseconds: 500_000_000)
    guard id > 0 else { throw NetworkError() }
    return "user_\(id)"
}

func loadProfile(id: Int) async throws -> String {
    let name = try await fetchUserName(id: id)
    return "Profile for \(name)"
}