Fix disposed issue when app shut down (#1876)

* Fix disposed issue when app shut down

* Update ServiceConnection.cs

Author: vicancy

src/Microsoft.Azure.SignalR/ServerConnections/ServiceConnection.cs

@@ -344,7 +344,7 @@ private async Task<bool> SkipHandshakeResponse(ClientConnectionContext connectio
             return false;
         }
 
-        private async Task ProcessOutgoingMessagesAsync(ClientConnectionContext connection, CancellationToken token = default)
+        private async Task ProcessOutgoingMessagesAsync(ClientConnectionContext connection, CancellationToken token)
         {
             try
             {
@@ -430,6 +430,11 @@ private async Task ProcessApplicationTaskAsyncCore(ClientConnectionContext conne
                 // application task can end when exception, or Context.Abort() from hub
                 await _connectionDelegate(connection);
             }
+            catch (ObjectDisposedException)
+            {
+                // When the application shuts down and disposes IServiceProvider, HubConnectionHandler.RunHubAsync is still running and runs into _dispatcher.OnDisconnectedAsync
+                // no need to throw the error out
+            }
             catch (Exception ex)
             {
                 // Capture the exception to communicate it to the transport (this isn't strictly required)