I need to send an instant message from the server to the client after the user has submitted a form in a browser.

I followed the Microsoft steps [here](https://learn.microsoft.com/en-us/aspnet/core/tutorials/signalr?view=aspnetcore-2.1&tabs=visual-studio) to set up a signalR connection, created a Hub class, signalr.js etc. 

The problem is that I can only invoke a message to all clients, but I need to invoke the message to the specific caller who initiated the request (otherwise everyone will get the message).

This is my POST Action in the HomeController.cs:

```
[HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> Submit(string signalRconnectionId, Dictionary<string, string> inputs)
    {
        //Invoke signal to all clients sending a message to initSignal WORKS FINE
        await _signalHubContext.Clients.All.SendAsync("initSignal", "This is a message from the server!");

        //Invoke signal to specified client where signalRConnectionId = connection.id DOES NOT WORK
        await _signalHubContext.Clients.Client(signalRconnectionId).SendAsync("initSignal", "This is a message from server to this client: " + signalRconnectionId);

        return RedirectToAction("Success", inputs);
    }

```

my client javascript file:

```
    //Create connection and start it
const connection = new signalR.HubConnectionBuilder()
    .withUrl("/signalHub")
    .configureLogging(signalR.LogLevel.Information)
    .build();
connection.start().catch(err => console.error(err.toString()));

console.log("connectionID: " + connection.id);
$("#signalRconnectionId").attr("value", connection.id);

//Signal method invoked from server
connection.on("initSignal", (message) => {

    console.log("We got signal! and the message is: " + message);

});

```

I have tried debugging the action method and I get correctly passed in the connectionId which is "0" (incrementing by 1 per connection)