function format$2 (obj) {
  var parameters = obj.parameters;
  var type = obj.type;

  if (!type || typeof type !== 'string' || !TOKEN_REGEXP.test(type)) {
    throw new TypeError('invalid type')
  }

  // start with normalized type
  var string = String(type).toLowerCase();

  // append parameters
  if (parameters && typeof parameters === 'object') {
    var param;
    var params = Object.keys(parameters).sort();

    for (var i = 0; i < params.length; i++) {
      param = params[i];

      var val = param.substr(-1) === '*'
        ? ustring(parameters[param])
        : qstring(parameters[param]);

      string += '; ' + param + '=' + val;
    }
  }

  return string
}
Proxy `Router#use()` to add middleware to the app router.
See Router#use() documentation for details.

If the _fn_ parameter is an express app, then it will be
mounted at the _route_ specified.

@public