Use status 204 for an emtpy response.

[philnash]

As in the updated answer to this question: https://stackoverflow.com/questions/49289113/twilio-11200-errors-in-sms-status-callback/49289677#49289677, 204 means OK, but with no body, which is what this endpoing is returning.

There's nothing like being rigorous with HTTP statuses to get your morning started.