code: func NewRawKVClient(pdAddrs []string, security config.Security) (*RawKVClient, error) {
  	pdCli, err := pd.NewClient(pdAddrs, pd.SecurityOption{
  		CAPath:   security.ClusterSSLCA,
  		CertPath: security.ClusterSSLCert,
  		KeyPath:  security.ClusterSSLKey,
  	})
  	if err != nil {
  		return nil, errors.Trace(err)
  	}
  	return &RawKVClient{
  		clusterID:   pdCli.GetClusterID(context.TODO()),
  		regionCache: NewRegionCache(pdCli),
  		pdClient:    pdCli,
  		rpcClient:   newRPCClient(security),
  	}, nil
  }
docs: // NewRawKVClient creates a client with PD cluster addrs.