code: 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));
      }
docs: Sends RAW command string to the server.
  @throws SocketException on connection error.