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. 

Note: The endpoint name is not available until the instance is fully up. 

I've looked at waiters but it uses different methods params, waitUntilDBInstanceAvailable takes 1 array as an argument per [documentation](http://docs.aws.amazon.com/aws-sdk-php/latest/class-Aws.Rds.RdsClient.html#_waitUntilDBInstanceAvailable). 

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

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

```