/**
  * Write session data
  * @link http://php.net/manual/en/sessionhandlerinterface.write.php
  * @param string $session_id The session id.
  * @param string $session_data <p>
  * The encoded session data. This data is the
  * result of the PHP internally encoding
  * the $_SESSION superglobal to a serialized
  * string and passing it as this parameter.
  * Please note sessions use an alternative serialization method.
  * </p>
  * @return bool <p>
  * The return value (usually TRUE on success, FALSE on failure).
  * Note this value is returned internally to PHP for processing.
  * </p>
  * @since 5.4.0
  */
 public function write($session_id, $session_data)
 {
     if (!$this->driver->has($path = $this->path . $session_id)) {
         $this->driver->create($path);
     }
     return $this->driver->put($path, $session_data);
 }