WebSocketException (0x80004005): The remote party closed the WebSocket connection without completing

我有一个使用 WebSocket 进行通信的 Xamarin 应用程序。 在客户端，我引用了 ClientWebSocket。

using (var client = new ClientWebSocket() { Options = { KeepAliveInterval = new TimeSpan(0,0,3,0) }})
{
    try
    {
        await client.ConnectAsync(requestUri, cancellationToken);
        do
        {
            WebSocketReceiveResult result = null;
            var buffer = new byte[ReceiveChunkSize];
            var message = new ArraySegment<byte>(buffer);
            do
            {
                result = await client.ReceiveAsync(message, cancellationToken);
                var receivedMessage = Encoding.UTF8.GetString(buffer, 0, result.Count);
                data.Append(receivedMessage);
                if (result.MessageType != WebSocketMessageType.Text)
                    break;

            } while (!result.EndOfMessage);

            TranslateData(data);
        } while (client.State == WebSocketState.Open && !cancellationToken.IsCancellationRequested);

该应用程序不断间歇性地抛出了异常：

System.Net.WebSockets.WebSocketException (0x80004005): The remote party closed the WebSocket connection without completing the close handshake.

服务器有一个测试网站，它似乎可以按预期运行。 看来问题出在客户端。 client.State 中的值为 Open。

这是什么问题呢？