function ReadableSVGStream(options) {
    if (!(this instanceof ReadableSVGStream)) {
      return new ReadableSVGStream(options);
    }
    stream.Readable.call(this, options);
    this.serializer = options.svgElement.getSerializer();
  }
A readable stream which offers a stream representing the serialization of a
given DOM element (as defined by domstubs.js).

@param {object} options
@param {DOMElement} options.svgElement The element to serialize