public async Task <Stream> GetWaveAudioAsync(AudioFormat outputFormat, string text, string voiceName, float rateChange, float pitchChange)
{
CheckAudioFormat(outputFormat);
var stream = await GetAudioDataStreamAsync(outputFormat, text, voiceName, rateChange, pitchChange)
.ConfigureAwait(false);
return(audioDecoder.ToWave(stream));
}