/// <summary>
/// Upon closing the window or exiting the application this is called to make sure the other users
/// no longer see the user who has left.
/// </summary>
/// <param name="user">User who has left the application.</param>
/// <returns></returns>
public async Task RemoveUser(User user)
{
var connectionId = Context.ConnectionId;
_users.Remove(connectionId);
await Clients.All.SendAsync("removeUser", _users.GetUsers());
}
public override async Task OnDisconnectedAsync(Exception exception)
{
string name = Context.User.Identity.Name;
_connections.Remove(name, Context.ConnectionId);
await Groups.RemoveFromGroupAsync(Context.ConnectionId, "Users");
await base.OnDisconnectedAsync(exception);
}