/// <summary>
/// Handles when a client gets disconnected.
/// </summary>
/// <param name="stopCalled">True, if stop was called on the client closing the connection gracefully;
/// false, if the connection has been lost for longer than the timeout.</param>
/// <returns></returns>
public override async Task OnDisconnectedAsync(Exception exception)
{
// Access VMController to set the ambient context.
VMController _ = VMController;
// Remove the controller on disconnection.
_vmControllerFactory.Remove(Context.ConnectionId);
// Allow middlewares to hook to the event.
await _hubPipeline.RunDisconnectionMiddlewaresAsync(Context);
await base.OnDisconnectedAsync(exception);
}