Blazor是一个基于WebAssembly的框架，用于在Web浏览器中构建客户端应用程序。它提供了一种使用C#语言构建Web应用程序的方式，包括在浏览器中实现实时通信的能力。然而，在使用WebSocket进行实时通信时，Blazor default implemention缺少了对WebSocket消息的解码支持。

要解决这个问题，可以使用JsonConvert来将WebSocket消息解码。下面是一个使用Newtonsoft.Json库进行WebSocket消息解码的示例：

在客户端：

private async Task ConnectAsync()
{
    var socket = new WebSocket("wss://localhost:5001/ws");
    socket.OnMessage += Socket_OnMessage;
            
    await socket.ConnectAsync();

    var request = new Request
    {
        Command = "subscribe",
        Symbol = "BTC/USDT"
    };
    var requestJson = JsonConvert.SerializeObject(request, Formatting.None);
    await socket.SendAsync(Encoding.UTF8.GetBytes(requestJson), WebSocketMessageType.Text, true);
}

private void Socket_OnMessage(object sender, MessageEventArgs e)
{
    var responseJson = Encoding.UTF8.GetString(e.Data);
    var response = JsonConvert.DeserializeObject(responseJson);

    // handle the response
}

在服务器端：

public async Task SendMessage(WebSocket socket, string message)
{
    var buffer = Encoding.UTF8.GetBytes(message);
    var segment = new ArraySegment(buffer);
    await socket.SendAsync(segment, WebSocketMessageType.Text, true, CancellationToken.None);
}

private async Task ReceiveAsync(WebSocket socket)
{
    while (socket.State == WebSocketState.Open)
    {
        var buffer = new byte[1024 * 4];
        var result = await socket.ReceiveAsync(new ArraySegment(buffer), CancellationToken.None);
        if (result.MessageType == WebSocketMessageType.Text)
        {
            var message = Encoding.UTF8.GetString(buffer, 0, result.Count);
            var request = JsonConvert.DeserializeObject(message);

            Response response;
            // handle the request and generate the response

            var responseJson = JsonConvert.SerializeObject(response, Formatting.None);
            await SendMessage(socket, responseJson);
        }
    }
}
``