Custom logger and middleware stack

Works as of commit 3ff70d6926.

use GuzzleHttp\Psr7;
use Monolog\Handler\ErrorLogHandler;
use Monolog\Logger;
use Psr\Log\LogLevel;
use SimplePie\HandlerStack;
use SimplePie\Middleware\Json\JsonFeed;
use SimplePie\Middleware\Xml\Atom;
use SimplePie\Middleware\Xml\Rss;
use SimplePie\SimplePie;

// Configure the logger.
$logger = new Logger('SimplePie');
$logger->pushHandler(new ErrorLogHandler(
    ErrorLogHandler::OPERATING_SYSTEM,
    LogLevel::DEBUG,
    true,
    false
));

// Configure the middleware stack.
$middleware = (new HandlerStack())
    ->append(new JsonFeed(), 'jsonfeed')
    ->append(new Atom()    , 'atom10')
    ->append(new Rss()     , 'rss20')
;

// Instantiate SimplePie.
$simplepie = (new SimplePie())
    ->setLogger($logger)
    ->setMiddlewareStack($middleware)
;

// Pass a PSR-7 stream to SimplePie for parsing.
$stream = Psr7\stream_for(file_get_contents(__DIR__ . '/releases.atom'));

// Specifically parses XML.
// Only applies the middleware that is registered as supporting XML feed types.
$parser = $simplepie->parseXml($stream, true);

// Reference the top-level feed object
$feed = $parser->getFeed();

// By default, all nodes return a `SimplePie\Type\Node` object with a `toString()` method defined.
// You can also handle various allowed serializations differently.
foreach ($feed->getItems() as $item) {
    switch ($item->getTitle()->getSerialization()) {
        case 'xhtml':
            // Custom XML stuff...
            break;
        case 'text':
        case 'html':
        default:
            echo $item->getTitle()->getValue();
    }
}