Situação:
React\EventLoop\Factory
[Deprecated] The Factory class exists as a convenient way to pick the best available event loop implementation.Sugestão:
use React\EventLoop\Loop;
require_once 'vendor/autoload.php';
$loop = Loop::get();
$loop->addPeriodicTimer(1, function () {
echo "1 segundo" . PHP_EOL;
});
$loop->run();