Data ConsumerData Source1a.Request data (POST/GET) indicating desired info with Prefer=respond-async1b.HTTP 202 Accepted w/ [polling location]loop2a.GET [polling location]2b.202 Accepted (w/ optional X-Progress header)3a.GET [polling location]3b.200 Ok w/ Json Response object listing [output file locations]4a.GET [output file location]4b.[output file]