Change effective on 10 August 2016
Add-ons that take a long time to create can now be provisioned in the background such that an add-on provider explicitly tells us when the provisioning process is complete. This means all add-ons will be able to take advantage of
heroku pg:wait-like semantics.
Background add-on provisioning allows for better orchestration around automated app and add-on creation. We will be extending the Heroku toolbelt to take advantage of this new feature soon.