(PECL pecl_http >= 0.10.0)
HttpResponse::setCacheControl — Set cache control
$control
   [, int $max_age = 0
   [, bool $must_revalidate = true
  ]] )Define a custom Cache-Control header, usually being private or public;
controlthe primary cache control setting
max_agethe max-age in seconds, suggesting how long the cache entry is valid on the client side
must_revalidatewhether the cached entity should be revalidated by the client for every request
   Returns TRUE on success, or FALSE if control does not match one of public, private or no-cache.