public function createTmpFile($suffix = null, $preserve = false)
        {
            $this->initRunFolder();

            $file = uniqid();

            if ($suffix) {
                $file .= '-' . $suffix;
            }

            $fileInfo = new \SplFileInfo($this->tmpRunFolder . DIRECTORY_SEPARATOR . $file);

            $this->filesystem->touch($fileInfo);
            $this->files[] = array(
                'file'  => $fileInfo,
                'preserve'  => $preserve
            );

            $this->filesystem->chmod($fileInfo, 0600);

            return $fileInfo;
        }