protected function getStdIn()
    {
        if ($this->stdIn && !feof($this->stdIn)) {
            return $this->stdIn;
        }

        try {
            $this->setStdIn();
        } catch (\Error $e) {
            throw new RuntimeException('Unable to read from STDIN', 0, $e);
        }

        return $this->stdIn;
    }