function ws(uri, protocols, opts) {
  var instance;
  if (protocols) {
    instance = new WebSocket(uri, protocols);
  } else {
    instance = new WebSocket(uri);
  }
  return instance;
}
WebSocket constructor.

The third `opts` options object gets ignored in web browsers, since it's
non-standard, and throws a TypeError if passed to the constructor.
See: https://github.com/einaros/ws/issues/227

@param {String} uri
@param {Array} protocols (optional)
@param {Object) opts (optional)
@api public