framework/web/CacheSession.php
public function writeSession($id, $data)
    {
        return $this->cache->set($this->calculateKey($id), $data, $this->getTimeout());
    }
public function writeSession($id, $data)
    {
        return $this->cache->set($this->calculateKey($id), $data, $this->getTimeout());
    }
Session write handler.
@internal Do not call this method directly.
@param string $id session ID
@param string $data session data
@return bool whether session write is successful