I was looking at 12 factor app principle and saw this statement. I believe this statement states that the application must respond to any backing service such database or message broker and connect to them irrespective of what they are. How does it differ from traditional way of connecting? For eg: in my microservice , I was defined database and kafka broker as user provided service in cloud foundry. It just provides the connection parameters as vcap service variables. I still have code to connect to a database and kafka broker which are entirely different. What does this statement signify and how does it differ from what we do in non-cloud environment?