title: Is there any way to detect client connected/disconnected?
body: <p>I'm looking for a technology in scope of ASP.NET Core for replacement of my WCF application, the server needs to know each client's connection status(in case client PC shutdown or network problems).</p>
  <p>as far as I know signalR is based on WebSocket in Transportation layer and Hubs API provides OnConnectedAsync and OnDisconnectedAsync virtual methods to manage and track connections, whereas web api or gRPC is based on HTTP protocol which is stateless.</p>
  <p><strong>so my question: is there any way or technology in ASP.NET Core that supports detecting client connected/disconnected ?</strong></p>
  <p>thanks a lot.</p>