title: Notification sending to single user and to admin role users using Signalr in .net core
body: <p>basicly i did a hub which sends notification when some action happens in repository . I want to change this to signle User sending , for example to send notificaiton if action happened on that user or to send all notifications to the admin role users.</p>
  <p>right now i have just a hub  and i use</p>
  <pre><code>                await _hubContext.Clients.All.SendAsync(&quot;displayNotification&quot;, &quot;&quot;);
  </code></pre>
  <p>and in html side</p>
  <pre><code>    const connection = new signalR.HubConnectionBuilder()
          .withUrl(&quot;/NotificationHub&quot;)
          .configureLogging(signalR.LogLevel.Information)
          .build();
  
      connection.on('displayNotification', () =&gt; {
          getNotification()
          toastr.info(&quot;You hava a new Notification&quot;);
      }
      );
  
      async function start() {
          try {
              await connection.start();
              console.log(&quot;connected&quot;);
          } catch (err) {
              console.log(err);
              setTimeout(() =&gt; start(), 5000);
          }
      };
  
      connection.onclose(async () =&gt; {
          await start();
      });
  
      start();
  </code></pre>