202 response for async command processing

[dickhardt]

In discussing lifecycle processing, some commands may require background processing or kick off a workflow. For example, Drupal queues up account deletion to a background task so the server is not blocked. Additionally, in Drupal account deletion can be configured that the user must verify account deletion in response to an email.

Proposal:

RP returns a 202 response with some JSON about delayed processing.

and when the command is completed, the RP would post to the command trigger URL (which likely needs a better name) provided by the OP and include the jti from the original command and the command response -- for example if there was an error, it would be an error response

[dickhardt]

we are going to have separate async and sync commands so a 202 will always be returned by an async command rather than the async / sync being a runtime decision by the RP