code: func New(params Parameters) (*Client, error) {
  	signer, err := LoadX509Signer(params.PrivateKeyPath, params.CertificatePath)
  	if err != nil {
  		return nil, err
  	}
  	return &Client{
  		Client: minter.NewTokenMinterPRPCClient(&prpc.Client{
  			C:    params.Client,
  			Host: params.Backend,
  			Options: &prpc.Options{
  				Retry:    params.Retry,
  				Insecure: params.Insecure,
  			},
  		}),
  		Signer: signer,
  	}, nil
  }
docs: // New returns new Client that uses PEM encoded keys and talks
  // to the server via pRPC.