What is a good way to go about designing this?

I want to develop a piece of software that other developers can use in their projects. It has to be active at runtime however, and perform some standard functionality every time the application runs. It is essentially software that provides extra functionality to the application developer and its users...

I'm not sure how I might do this, and my google-fu has not been strong enough to find a definite answer.

Counting Distinct Users in Real-Time With Redis Using Low Memory

If you are developing an event-based application that handles many requests from different users, you most likely want to count distinct user action within a sliding window or a specified time range.

One of the quickest ways to count distinct user is to prepare an SQL like SELECT count(distinct user) from ACTION_TABLE. But, this might be expensive if there are millions of records produced in real time.

Windows 10 May 2019 Update

In keeping with tradition, Microsoft has released the latest update before resolving a number of outstanding issues. But at least they now provide a more centralized location for getting update information. The home page (dashboard) can be found here and the specific page for the latest update can be found here.