method is_connected added

__init__.py

@@ -70,6 +70,9 @@ class tcp_base(object):
         self.__queue__.enqueue(5, self.__receive_task__, rx_log_lvl)
         self.__queue__.run()
 
+    def is_connected(self):
+        return self.__connection__ is not None
+
     def client_address(self):
         """
         :return: The client address.