docs: function rewrite(req, res) {
  
    /* istanbul ignore next: tough to mock fs write error */
    function onError(err) {
      this.conf.removeAllListeners('error');
      this.conf.removeAllListeners('write');
      res.send(err);
    }
  
    function onWrite() {
      this.conf.removeAllListeners('error');
      this.conf.removeAllListeners('write');
      res.send(null, Constants.OK);
    }
  
    this.conf.once('error', onError.bind(this));
    this.conf.write(this.conf.getFile(), onWrite.bind(this));
  }