title: Codeigniter output class doesn't contain http 429 status code
body: <p>I've been using codeigniter for development and making use of the output class (<a href="https://www.codeigniter.com/user_guide/libraries/output.html" rel="nofollow noreferrer">https://www.codeigniter.com/user_guide/libraries/output.html</a>) to make it easy to send correct status codes, headers and json responses.</p>
  <p>However, after trying to debug an issue I've had for a while, I realised that the set_status_header function implements the status codes in RFC 2616 (<a href="https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html" rel="nofollow noreferrer">https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html</a>) but not the additional status codes defined in RFC 6585 (<a href="https://www.rfc-editor.org/rfc/rfc6585" rel="nofollow noreferrer">https://www.rfc-editor.org/rfc/rfc6585</a>). This means that I can't send a 429 (Too many requests) status code.</p>
  <p>Is there an updated version of the output class that supports this or should I just use php's header() function to deal with this?</p>