WebGL - Streaming of 'ogg' on this platform is not supported

I've got an .ogg file up on the server that I'd like to download and play at runtime. I've got some code that works in the editor, but doesn't work in a WebGL deploy. In the WebGL deploy, I get the following error:

Streaming of 'ogg' on this platform is not supported.

Well, I'm not trying to stream it. In fact I'd prefer for the audio to be fully downloaded before attempting playback.

Here's the code I'm testing with:

 using UnityEngine;
 using UnityEngine.UI;
 using System.Collections;
 
 public class test_dynamic_audio : MonoBehaviour
 {
     public Text txt_message;
 
     private AudioSource _source;
 
     // Use this for initialization
     IEnumerator Start()
     {
         string url;
 
         url = "http://www.domain.com/url/to/audio.ogg";
 
         _source = GetComponent<AudioSource>();
 
         yield return new WaitForSeconds(0.5f);
 
         WWW www = new WWW(url);
         yield return www;
 
         _source.clip = www.GetAudioClip(false, false, AudioType.OGGVORBIS);
 
         yield return new WaitForSeconds(0.5f);
         
         _source.Play();
     }
     
     // Update is called once per frame
     void Update()
     {
         txt_message.text = "LOADING...";
 
         if (_source.clip != null)
         {
             txt_message.text = "LOADED.";
 
             if (_source.clip.isReadyToPlay)
             {
                 if (_source.isPlaying)
                 {
                     txt_message.text = "PLAYING.";
                 }
             }
         }
     }
 }

Any ideas on how to properly download audio and play it in WebGL?