add debug

Sources/Punchnet/SDLSuperClient.swift

@@ -101,12 +101,13 @@ actor SDLSuperClient {
                 group.addTask {
                     while !Task.isCancelled {
                         await self.ping()
-                        try? await Task.sleep(nanoseconds: 5 * 1_000_000_000)
+                        try await Task.sleep(nanoseconds: 5 * 1_000_000_000)
                     }
                     NSLog("[SDLSuperClient] heartbeat cancelled")
                 }
                 
                 try await group.waitForAll()
+                NSLog("[SDLSuperClient] group closed")
             }
         }
     }