asyncRequest( method, url, [body], [params] )

import http from 'k6/http';

const url = 'https://httpbin.test.k6.io/post';

export default async function () {
  const data = { name: 'Bert' };

  // Using a JSON string as body
  let res = await http.asyncRequest('POST', url, JSON.stringify(data), {
    headers: { 'Content-Type': 'application/json' },
  });
  console.log(res.json().json.name); // Bert

  // Using an object as body, the headers will automatically include
  // 'Content-Type: application/x-www-form-urlencoded'.
  res = await http.asyncRequest('POST', url, data);
  console.log(res.json().form.name); // Bert
}

import http from 'k6/http';

export default async () => {
  const urlOne = `https://httpbin.test.k6.io/delay/${randomInt(1, 5)}`
  const urlTwo = `https://httpbin.test.k6.io/delay/${randomInt(1, 5)}`
  const urlThree = `https://httpbin.test.k6.io/delay/${randomInt(1, 5)}`

  const one = http.asyncRequest('GET', urlOne);
  const two = http.asyncRequest('GET', urlTwo);
  const three = http.asyncRequest('GET', urlThree);

  console.log('Racing:')
  console.log(urlOne);
  console.log(urlTwo);
  console.log(urlThree);

  const res = await Promise.race([one, two, three])
  console.log('winner is', res.url, 'with duration of', res.timings.duration+'ms');
}

function randomInt(min, max) {
  return Math.floor(Math.random() * (max - min) + min);
}