Suggest an idea for ExpressionEngine

Is your feature request related to a problem? Please describe.
When we want to return a response as an Ajax response there is no way to set any headers.

Describe the solution you'd like
In the _display function there is a block of code that handles this:

// Are there any server headers to send?
if (count($this->headers) > 0) {
    foreach ($this->headers as $header) {
        @header($header[0], $header[1]);
    }
}

It would be great if that logic was copied into the send_ajax_response just before the json_encode call.
This would give the ability to set values for a caching layer that sits in front of the responses, like so

$expires = gmdate('D, d M Y H:i:s', time() + $cache_age) . ' GMT';
ee()->output->set_header("Cache-Control: public, max-age={$cache_age}");
ee()->output->set_header('Expires: ' . $expires);

Cache-Control is just my particular use case, but this could be used for setting custom headers to pass all kinds off info back. The nice thing is, in our custom add-ons we can set what values we please and the function will just loop over and set them.

Teachability, Documentation, Adoption, Migration Strategy
We could update https://docs.expressionengine.com/latest/development/legacy/libraries/output.html#send_ajax_responsemsg-statuscode--false so that the first example could show an example of set_header getting used before the actual send_ajax_response call.

• [y] I am capable and would like to work on implementation of this feature if it is considered.