title: PhantomJs uses several TCP connections when loading one page
body: <p>I used PhantomJs to crawl some websites and found out it open several TCP connections when loading even one page. For example, the following is my try.js:</p>
  
  <pre><code>var args = require('system').args;
  var page = require('webpage').create();
  var url = args[1];
  page.open(url, function(status) {
    var title = page.evaluate(function() {
      return document.title;
    });
  console.log('Page title is ' + title);
  //page.close();
  });
  </code></pre>
  
  <p>I tried </p>
  
  <blockquote>
    <p>phantomjs try.js <a href="http://www.google.com" rel="nofollow">http://www.google.com</a></p>
  </blockquote>
  
  <p>and found out it used 4 connections. I know calling "page.close()" will close all connections. But such issue may still result in large number of concurrent connections if I use many phantomjs processes. Does this happen because PhantomJs does not use persistent HTTP? Any solutions?</p>