Function handshake

packages/socket.io-cluster-engine/test/util.ts:11–17

(port: number)

}

export async function handshake(port: number) {
  const res = await fetch(url(port));
  expect(res.status).to.eql(200);

  const body1 = await res.text();
  return JSON.parse(body1.substring(1)).sid;
}