AnnouncementController.cs

using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.SignalR;

namespace Practical.AspNetCore.SignalR
{
    public class AnnouncementController : Controller 
    {
        private IHubContext<MessageHub> _hubContext;

        public AnnouncementController(IHubContext<MessageHub> hubContext)
        {
            _hubContext = hubContext;
        }
    }
}