public function get($block = false)
    {
        if ($this->block != $block) {
            $this->pipe->setBlock($block);
            $this->block = $block;
        }
        $len = $this->pipe->read(4);
        if ($len === false) {
            throw new \RuntimeException('read pipe failed');
        }

        if (strlen($len) === 0) {
            return null;
        }
        $len = unpack('N', $len);
        if (empty($len) || !array_key_exists(1, $len) || empty($len[1])) {
            throw new \RuntimeException('data protocol error');
        }
        $len = intval($len[1]);

        $value = '';
        while (true) {
            $temp = $this->pipe->read($len);
            if (strlen($temp) == $len) {
                return $temp;
            }
            $value .= $temp;
            $len -= strlen($temp);
            if ($len == 0) {
                return $value;
            }
        }
    }