func waitUntilAwsDbInstanceIsAvailableAfterUpdate(id string, conn *rds.RDS, timeout time.Duration) error {
stateConf := &resource.StateChangeConf{
Pending: resourceAwsDbInstanceUpdatePendingStates,
Target: []string{"available", "storage-optimization"},
Refresh: resourceAwsDbInstanceStateRefreshFunc(id, conn),
Timeout: timeout,
MinTimeout: 10 * time.Second,
Delay: 30 * time.Second, // Wait 30 secs before starting
}
_, err := stateConf.WaitForState()
return err
}