code: function Reader (opts) {
    if (!(this instanceof Reader)) {
      return new Reader(opts);
    }
    Transform.call(this, opts);
  
    this._bytes(4, this._onRiffID);
  }
docs: The `Reader` class accepts a WAV audio file written to it and outputs the raw
  audio data with the WAV header stripped (most of the time, PCM audio data will
  be output, depending on the `audioFormat` property).
  
  A `"format"` event gets emitted after the WAV header has been parsed.
  
  @param {Object} opts optional options object
  @api public