public static async Task OnMessageAsync(HttpApiClient api, MessageContext message)
        {
            if (message.RawMessage == "hello")
            {
                await api.SendMessageAsync(message.Endpoint, "Hello, WudiLib!");
                // Endpoint 代表消息接收/发送的节点。使用 Endpoint 可以让 bot 同时处理私聊和群聊消息，而无需分别编写代码。
            }
            else if (message.RawMessage == "1")
            {
                var t = message.Content.Fix();
                Bitmap bmp = new Bitmap(100, 100);
                var mms = new MemoryStream();
                var bm = new Bitmap(100, 200);
                using (var g = Graphics.FromImage(bm))
                {
                    g.Clear(Color.Yellow);
                }
                bm.Save(mms, System.Drawing.Imaging.ImageFormat.Png);
                await api.SendPrivateMessageAsync(600000003, "tst1");
                await api.SendPrivateMessageAsync(600000003, new Message("mytst") + Message.ByteArrayImage(mms.ToArray()));
            }
            else if (message.RawMessage == "2")
            {
                await api.SendPrivateMessageAsync(600000003, "tst1");
                await api.SendPrivateMessageAsync(600000003, Message.LocalImage(@"Q:\DownloadBox\6951.png"));
            }
            else if (message.RawMessage == "3")
            {
                await api.SendPrivateMessageAsync(600000003, "tst3");
                await api.SendPrivateMessageAsync(600000003, Message.NetImage(@"https://www.sogou.com/web/img/logo115_50.png?v=5"));
            }else if (message.RawMessage == "4")
            {
                await api.SendPrivateMessageAsync(600000003, "tst4");
                await api.SendPrivateMessageAsync(600000003, Message.LocalImage(@"6951.png"));
            }
        }