func Test() (*rpcclient.Client, error) {
    // Only override the handlers for notifications you care about.
    // Also note most of these handlers will only be called if you register
    // for notifications.  See the documentation of the rpcclient.
    // NotificationHandlers type for more details about each handler.
    ntfnHandlers := rpcclient.NotificationHandlers{
        OnBlockConnected: func(blockHeader []byte, transactions [][]byte) {
            log.Printf("Block connected: %v %v", blockHeader, transactions)
        },
        OnBlockDisconnected: func(blockHeader []byte) {
            log.Printf("Block disconnected: %v", blockHeader)
        },
    }

    // Connect to local dcrd RPC server using websockets.
    certs, err := ioutil.ReadFile(Env.DcrdCertFilePath)
    if err != nil {
        return nil, err
    }
    connCfg := &rpcclient.ConnConfig{
        Host:         fmt.Sprintf("%s:%d", Env.DcrdHost, Env.DcrdPort),
        Endpoint:     "ws",
        User:         Env.DcrdUser,
        Pass:         Env.DcrdPass,
        Certificates: certs,
    }
    client, err := rpcclient.New(connCfg, &ntfnHandlers)
    if err != nil {
        return nil, err
    }

    // Register for block connect and disconnect notifications.
    if err := client.NotifyBlocks(); err != nil {
        return nil, err
    }

    c := make(chan os.Signal)
    signal.Notify(c, os.Interrupt, syscall.SIGTERM)
    go func() {
        <-c
        // For this example gracefully shutdown the client after 10 seconds.
        // Ordinarily when to shutdown the client is highly application
        // specific.
        client.Shutdown()

        // Wait until the client either shuts down gracefully (or the user
        // terminates the process with Ctrl+C).
        client.WaitForShutdown()
    }()

    addr, err := client.GetNewAddress("default")
    log.Println(addr, err) // error here
    return client, nil
}