Fix delayed message visibility timing issue

Author: tavallaie

tests/test_integration.py

@@ -60,7 +60,7 @@ def test_send_message_with_delay(self):
         msg_id = self.queue.send(self.test_queue, self.test_message, delay=5)
         message = self.queue.read(self.test_queue, vt=20)
         self.assertIsNone(message, "Message should not be visible yet")
-        time.sleep(5)
+        time.sleep(6)
         message: Message = self.queue.read(self.test_queue, vt=20)
         self.assertIsNotNone(message, "Message should be visible after delay")
         self.assertEqual(message.message, self.test_message)