Biskilog_Server_Manager/ServerManager/Hubs/SalesHub.cs

using Microsoft.AspNetCore.SignalR;
using ServerManager.Interface;

namespace ServerManager.Hubs
{
    public class SalesHub : Hub<ISalesHub>
    {
        public override Task OnConnectedAsync()
        {
            Clients.
            return base.OnConnectedAsync();
        }
        public async Task Publish(string a_companyId)
        {
            await Clients.OthersInGroup(a_companyId).AddTransaction();
        }
    }
}