Refactor sync.client.conncect & sync.server.start

Reopen ThreadLoop if  stopped previously analogous to init
Fixes FreeOpcUa#1364

asyncua/sync.py

@@ -249,9 +249,12 @@ def application_uri(self):
     def application_uri(self, value):
         self.aio_obj.application_uri = value
 
-    @syncmethod
     def connect(self) -> None:
-        pass
+        if not self.tloop.is_alive():
+            self.tloop = ThreadLoop()
+            self.tloop.start()
+            self.close_tloop = True
+        self.tloop.post(self.aio_obj.connect())
 
     def disconnect(self) -> None:
         try:
@@ -592,9 +595,12 @@ def register_namespace(self, url):
     def get_namespace_array(self):
         pass
 
-    @syncmethod
     def start(self):
-        pass
+        if not self.tloop.is_alive():
+            self.tloop = ThreadLoop()
+            self.tloop.start()
+            self.close_tloop = True
+        self.tloop.post(self.aio_obj.start())
 
     def stop(self):
         self.tloop.post(self.aio_obj.stop())