Short-circuit lock acquire in conn.close()

Author: dpkp

kafka/conn.py

@@ -803,6 +803,8 @@ def close(self, error=None):
                 will be failed with this exception.
                 Default: kafka.errors.KafkaConnectionError.
         """
+        if self.state is ConnectionStates.DISCONNECTED:
+            return
         with self._lock:
             if self.state is ConnectionStates.DISCONNECTED:
                 return