always return content when creating except for large content

[Inkimar]

" In the section http://jsonapi.org/format/#crud-creating the datandard indicates: "The response MUST also include a document that contains the primary resource created.". For large media objects, moving extremely large data from the server back to the client after submission would be prohibitive from the bandwidth perspective " - from https://github.com/gnewton/test/blob/master/req2.md

proposed solution:
for large content , part of this submission is sha1, this sha1 is then compared to the sha1 that the server creates from the received content. If they match then only the sha1 is returned (and not the large content) .
If they don't match we will return a HTTP status code 400.