如何调用依赖于rx网络调用的非rx网络调用

import io.reactivex.Observable;
import io.reactivex.schedulers.Schedulers;
import retrofit2.Call;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;

public class NetworkUtils {
    private Retrofit retrofit;

    public NetworkUtils() {
        retrofit = new Retrofit.Builder()
                .baseUrl("https://api.example.com/")
                .addConverterFactory(GsonConverterFactory.create())
                .build();
    }

    public Observable<String> performNonRxNetworkCall() {
        return Observable.fromCallable(() -> {
            // 执行非Rx网络调用
            Call<String> call = retrofit.create(ApiService.class).getData();
            Response<String> response = call.execute();
            if (response.isSuccessful()) {
                return response.body();
            } else {
                throw new Exception("Network request failed");
            }
        }).subscribeOn(Schedulers.io());
    }
}

// 使用示例
public class Main {
    public static void main(String[] args) {
        NetworkUtils networkUtils = new NetworkUtils();
        Observable<String> observable = networkUtils.performNonRxNetworkCall();

        observable.subscribe(
                result -> {
                    // 处理网络请求成功的结果
                    System.out.println("Network request succeeded: " + result);
                },
                error -> {
                    // 处理网络请求失败的情况
                    System.out.println("Network request failed: " + error.getMessage());
                }
        );
    }
}