Using aws php sdk's waitUntilDBInstanceAvailable()

I'm trying to use the waitUntilDBInstanceAvailable() to wait for my newly created instance to be available so that I can grab the endpoint name. I've looked at waiters but it uses different methods. waitUntilDBInstanceAvailable takes 1 array as an argument per documentation.

    $results = $rds->waitUntilDBInstanceAvailable([
        'DBInstanceIdentifier' => 'my-rds-instance'
    ]);

    $instanceEndPoint = $results->DBInstances->EndPoint // Theoretically