Releases the lock for the given Request.
Request $request A Request instance:
Boolean False if the lock file does not exist or cannot be unlocked, true otherwise
Overrides StoreInterface::unlock
public function unlock(Request $request) {
$file = $this
->getPath($this
->getCacheKey($request) . '.lck');
return is_file($file) ? @unlink($file) : false;
}