code: func (p *WebPage) Render(filename, format string, quality int) error {
  	req := map[string]interface{}{"ref": p.ref.id, "filename": filename, "format": format, "quality": quality}
  	return p.ref.process.doJSON("POST", "/webpage/Render", req, nil)
  }
docs: // Render renders the web page to a file with the given format and quality settings.
  // This supports the "PDF", "PNG", "JPEG", "BMP", "PPM", and "GIF" formats.