title: How to run nightwatch.js tests in parallel?
body: <p>I came across this question: 
  <a href="https://stackoverflow.com/questions/37271495/how-can-i-run-multiple-tests-in-parallel-with-js-nightwatchjs">How can I run multiple tests in parallel with JS/nightwatchjs?</a></p>
  
  <p>But I want to execute multiple tests in parallel in the chrome browser only, in multiple chrome driver sessions.</p>
  
  <p>I am used to java-testng-selenium based test suites where I can specify in the testng.xml file that I want to run multiple test classes or test methods in parallel and the framework does that exactly. If I specify in testng.xml that I want multiple test methods to execute in parallel in 4 threads, 4 chrome browser sessions pop-up and 4 test methods are executed in parallel. </p>
  
  <p>Here's an example with a thread-count=2: <a href="https://github.com/adityai/testng-parallelsample/blob/master/methods-test-testng.xml" rel="nofollow noreferrer">https://github.com/adityai/testng-parallelsample/blob/master/methods-test-testng.xml</a></p>
  
  <p>How can I do the same with nightwatch.js?</p>