private function sendCommandInternal($command, $params)
    {
        $written = @fwrite($this->_socket, $command);
        if ($written === false) {
            throw new SocketException("Failed to write to socket.\nRedis command was: " . $command);
        }
        if ($written !== ($len = mb_strlen($command, '8bit'))) {
            throw new SocketException("Failed to write to socket. $written of $len bytes written.\nRedis command was: " . $command);
        }
        return $this->parseResponse(implode(' ', $params));
    }