code: function Writer (metaint, opts) {
    if (!(this instanceof Writer)) {
      return new Writer(metaint, opts);
    }
    if (!isFinite(metaint)) {
      throw new Error('Writer requires a "metaint" number');
    }
    Transform.call(this, opts);
  
    this.metaint = +metaint;
  
    this._queue = [];
  
    this._passthrough(this.metaint, this._inject);
  }
docs: The `Writer` class is a duplex stream that accepts raw audio/video data and
  passes it through untouched. It also has a `queue()` function that will
  queue the Writer to inject the metadata into the stream at the next "metaint"
  interval.
  
  @param {Number} metaint the number of raw bytes that should be placed in between "metadata" blocks.
  @param {Object} opts optional options object
  @api public