Send a Reason for success results

Currently it seems the Reason portion of the response object payload can only be controlled in failure scenarios.

I'd like to send a Reason message for successful creates / updates in order to make it easier for system operators to understand the impact of the action taken. For me, I am implementing a schema migrator so I'd like to output that "3 migrations have executed successfully".

Start by locating the response object handling for successful create and update operations and compare it with the existing failure response path. Confirm how the Reason field is currently populated, then verify that a successful operation can return an operator-supplied message such as the migration count.

Written by the indexing model from the issue text.