public async Task <IActionResult> SendMessage([FromBody] Message message)
        {
            connection = new HubConnectionBuilder()
                         .WithUrl(hubUrl)
                         .Build();

            await connection.StartAsync();

            var aesEncriptedMesage = AesCryptoHelper.EncryptString_Aes(message.MessageContent);
            await connection.InvokeAsync("SendMessage", message.User, aesEncriptedMesage);

            return(new OkResult());
        }
        private async void sendButton_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                var aesEncriptedMesage = AesCryptoHelper.EncryptString_Aes(messageTextBox.Text);

                await connection.InvokeAsync("SendMessage", userTextBox.Text, aesEncriptedMesage);
            }
            catch (Exception ex)
            {
                messagesList.Items.Add(ex.Message);
            }
        }