title: Puppeteer: multiple user requests to the same Chromium instance
body: <p>To hopefully save on system resources I want to run user requests through the same Chromium version in Puppeteer.</p>
  
  <p>If a user submits a form on my site which calls Puppeteer, and Chromium is already running, how can I use the same Chromium instance up to a maximum of 4 tabs?</p>
  
  <p>If there are more than 4 tabs open in the Chromium instance then I want to launch a new Chromium instance. </p>
  
  <p>How can I achieve this? Would I need to store the <code>browserWSEndpoint</code> of the Chromium instance to a file and then retrieve it every time a new user submits a request? (This would be using <code>browserWSEndpoint</code> with <code>puppeteer.connect()</code>).</p>
  
  <p>If I have to do it this way, lets say there are 2 Chromium browsers active. The first most recent browser has the maximum four open tabs, so I could not use this browser. I would then check the next <code>browserWSEndpoint</code> and, if there are less than 4 open tabs, create a new page; and if not, launch a new browser.</p>
  
  <p>Does that sound OK?</p>