\Amp\run(function() {
    $connection = new Amp\Mysql\Connection("host=".DB_HOST.";user=".DB_USER.";pass=".DB_PASS);
    yield $connection->connect();
    $resultSet = yield $connection->query("SELECT 10");
    $rows = yield $resultSet->fetchAll();
    var_dump($rows); // Array(1) { 0 => Array(1) { 0 => 10 } }
});