// Headers are already sent!
throw new ResponseHeadersAlreadySentException($this, self::EXCEPTION_HEADERS_ALREADY_SENT);
} elseif (!headers_sent()) {
// Send headers out
// Headers are already sent!
throw new ResponseHeadersAlreadySentException($this, self::EXCEPTION_HEADERS_ALREADY_SENT);
} elseif (!headers_sent()) {
// Send headers out