This asset is no longer needed, since Unity 2021.3 you can do the same with following code:
IEnumerator LoadAndPlay(string uri)
{
using (UnityWebRequest www = UnityWebRequestMultimedia.GetAudioClip(uri, AudioType.MPEG))
{
yield return www.SendWebRequest();
if (www.result == UnityWebRequest.Result.ConnectionError || www.result == UnityWebRequest.Result.ProtocolError)
{
Debug.LogError("Error: " + www.error);
}
else
{
AudioClip clip = DownloadHandlerAudioClip.GetContent(www);
audioSource.clip = clip;
audioSource.Play();
}
}
}