Method constructor

test/common/websocket-server.js:9–20

({
    port = 0,
    server,
    customHandleUpgradeHeaders = [],
  })

class WebSocketServer {
  constructor({
    port = 0,
    server,
    customHandleUpgradeHeaders = [],
  }) {
    this.port = port;
    this.server = server || http.createServer();
    this.clients = new Set();
    this.customHandleUpgradeHeaders = customHandleUpgradeHeaders;

    this.server.on('upgrade', this.handleUpgrade.bind(this));
  }

  start() {
    return new Promise((resolve) => {