…n the MemcachedSessionHandler (Alessandro Loffredo)This PR was merged into the 3.4 branch.Discussion----------[Fix][3.4][HttpFoundation] Fix the updating of timestamp in the MemcachedSessionHandler| Q             | A| ------------- | ---| Branch?       | 3.4| Bug fix?      | yes| New feature?  | no| BC breaks?    | no| Deprecations? | no| Tests pass?   | yes| License       | MITConditions: Symfony 3.4, PHP7 and sessions handled over memcache.Apparently `memcached::touch()` returns `false` on a subsequent call with the same parameters. Since `updateTimestamp` is used in `AbstractSessionHandler::write()````public function write($sessionId, $data)    {        if (\PHP_VERSION_ID < 70000 && $this->prefetchData) {            $readData = $this->prefetchData;            $this->prefetchData = null;            if ($readData === $data) {                return $this->updateTimestamp($sessionId, $data);            }        }...```the result is that `write()` will return `false` on **any subsequent request within the same second** causing the following error:```HP Fatal error:  Uncaught Symfony\Component\Debug\Exception\ContextErrorException: Warning: session_write_close(): Failed to write session data (user). Please verify that the current setting of session.save_path is correct (/var/lib/php/sessions) in Unknown:0Stack trace:#0 [internal function]: Symfony\Component\Debug\ErrorHandler->handleError(2, 'session_write_c...', 'Unknown', 0, NULL)#1 [internal function]: session_write_close()#2 {main}  thrown in Unknown on line 0```Can be reproduced on `symfony/skeleton:3.4` adding the following code to `public/index.php` and performing two consecutive requests:```$session = $kernel->getContainer()->get('session');$session->set("foo", "bar");```Commits-------d007469 fix the updating of timestamp in the MemcachedSessionHandler