Support for uncommon HTTP Status codes and how to set custom headers?

Hi, we have a resource that takes a while to create and want to return HTTP 202, and in general want to follow the conventions laid out here: https://farazdagi.com/posts/2014-10-16-rest-long-running-jobs/.
See here for a discussion of HTTP and long running processes: https://softwareengineering.stackexchange.com/questions/316208/http-status-code-for-still-processing.

[isc-tleavitt]

@mfortuna-isc can you elaborate on the custom headers use case?

Re: long-running processes, I think it would be good to build generalized background process support into isc.rest.