In feed-io 2.2, I introduced a Factory class built to get a FeedIo instance in one single line of code :
$feedIo = \FeedIo\Factory::create()->getFeedIo();
Obviously this works assuming that you installed feed-io using Composer and you have included vendor/autoload.php before.
Factory’s main method : Factory::create()
The factory comes with the ability to configure feed-io before getting its main class. For that, you will provide one or two configuration arrays depending on which dependency you want to configure.