如何为IBM Watson unity SDK自定义文本到语音转换语音？

using IBM.Watson.TextToSpeech.V1;
using IBM.Cloud.SDK.Utilities;
using UnityEngine;

public class TextToSpeechExample : MonoBehaviour
{
    private TextToSpeechService textToSpeechService;

    void Start()
    {
        // 创建Watson TextToSpeech服务的实例
        textToSpeechService = new TextToSpeechService();

        // 设置Watson服务的凭证和URL
        textToSpeechService.SetCredentials("<your-iam-apikey>", "<your-service-url>");

        // 调用Synthesize方法进行文本到语音转换
        textToSpeechService.Synthesize(HandleSynthesize, "<your-text>", VoiceType.en_US_Allison, AudioFormat.WAV);
    }

    private void HandleSynthesize(byte[] audioData)
    {
        // 将生成的语音保存到本地文件或者直接播放
        // SaveToFile(audioData, "<output-file-path>");
        // PlayAudio(audioData);
    }
}