public async Task AddToGroup(string groupName) { await Groups.AddToGroupAsync(Context.ConnectionId, groupName); await Clients.Group(groupName).SendAsync("Send", $"{Context.ConnectionId} has joined the group {groupName}."); } public async Task RemoveFromGroup(string groupName) { await Groups.RemoveFromGroupAsync(Context.ConnectionId, groupName); await Clients.Group(groupName).SendAsync("Send", $"{Context.ConnectionId} has left the group {groupName}."); }