code: function(audio) {
        var self = this || Howler;
  
        // Don't add audio to the pool if we don't know if it has been unlocked.
        if (audio._unlocked) {
          self._html5AudioPool.push(audio);
        }
  
        return self;
      }
docs: Return an activated HTML5 Audio object to the pool.
  @return {Howler}