code: func (client *GRPCClient) SetServerRootCAs(serverRoots [][]byte) error {
  
  	// NOTE: if no serverRoots are specified, the current cert pool will be
  	// replaced with an empty one
  	certPool := x509.NewCertPool()
  	for _, root := range serverRoots {
  		err := AddPemToCertPool(root, certPool)
  		if err != nil {
  			return errors.WithMessage(err, "error adding root certificate")
  		}
  	}
  	client.tlsConfig.RootCAs = certPool
  	return nil
  }
docs: // SetServerRootCAs sets the list of authorities used to verify server
  // certificates based on a list of PEM-encoded X509 certificate authorities