use EventSource\EventSender;
use EventSource\EventBufferInterface;
use EventSource\Event;

$sender = new EventSender(); // Create new sender instance
// Configure sender adding listeners
$sender->addStartListener(
    function () {
        // What do you want when I'm starting?
    }
);
$sender->addWriteListener(
    function (EventBufferInterface $buffer) {
        $event = new Event('ping', 'ping at: ' . time());
        $buffer->write($event);
    }
);
$sender->addStopListener(
    function () {
        // What do you want when I'm stopping?
    }
);

$sender->send(); 

use EventSource\EventBufferInterface;
use EventSource\Event;
use EventSource\EventSender;

// If you want to use a custom buffer you can extend \EventSource\EventBufferInterface
class MyOwnBuffer implements EventBufferInterface {
    public function write(Event $event) : void 
    {
        echo 'MyOwnBuffer write this';
    }
}

// And the set to EventSender instance
$sender = new EventSender();
$sender->setBuffer(new MyOwnBuffer());