title: Vertx - Stop a verticle instance
body: <p>I have this vertx code :</p>
  
  <pre><code>DeploymentOptions deploymentOptions=new DeploymentOptions();
  deploymentOptions.setInstances(2);
  </code></pre>
  
  <p>I want to know how to stop or kill one instance of the set instances.</p>
  
  <p>Thanks.</p>