Gaufrette\Adapter\Ftp::mtime PHP Method

    public function mtime($key)
    {
        $this->ensureDirectoryExists($this->directory, $this->create);
        $mtime = ftp_mdtm($this->getConnection(), $this->computePath($key));
        // the server does not support this function
        if (-1 === $mtime) {
            throw new \RuntimeException('Server does not support ftp_mdtm function.');
        }
        return $mtime;
    }