public function deleteMulti(array $keys)
{
// check the current values to see if they currently exists, so we can
// properly return true/false as would be expected from KeyValueStore
$items = $this->getMulti($keys);
$success = array();
foreach ($keys as $key) {
$success[$key] = array_key_exists($key, $items);
}
// only attempt to store those that we've deleted successfully to local
$values = array_intersect_key($success, array_flip($keys));
if (empty($values)) {
return array();
}
// mark all as expired in local cache (see comment in delete())
$this->local->setMulti($values, -1);
$this->defer->deleteMulti(array_keys($values));
return $success;
}