Activates AWS Shield Advanced for an account.
shield_create_subscription()svc$create_subscription()
As part of this request you can specify EmergencySettings that
automaticaly grant the DDoS response team (DRT) needed permissions to
assist you during a suspected DDoS attack. For more information see
Authorize the DDoS Response Team to Create Rules and Web ACLs on Your Behalf.
To use the services of the DRT, you must be subscribed to the Business Support plan or the Enterprise Support plan.
When you initally create a subscription, your subscription is set to be
automatically renewed at the end of the existing subscription period.
You can change this by submitting an UpdateSubscription request.