https://blogs.sap.com/2013/12/09/to-push-or-pull-that-is-the-question/
https://en.wikipedia.org/wiki/Push_technology
https://en.wikipedia.org/wiki/Pull_technology
https://blogs.sap.com/2013/12/09/to-push-or-pull-that-is-the-question/
https://en.wikipedia.org/wiki/Push_technology
https://en.wikipedia.org/wiki/Pull_technology