use Cerpus\PubSub\Connection\ConnectionFactory;
use Cerpus\PubSub\PubSub;

$connectionFactory = new ConnectionFactory('localhost', 5672, 'guest', 'guest', '/');
$pubSub = new PubSub($connectionFactory->connect());

// publish your own messages
$pubSub->publish('some_other_topic', 'some data');

// listen for incoming messages
$pubSub->subscribe('subscriber_name', 'some_topic', function (string $data) {
    // do something with the data
    echo "$data\n";
});
$pubSub->listen();