> In this post we take you on a walkthrough on how you can use DataFusion

Thought it was gonna be a "build your own SQLite" or something

this post feels like it's skipping over a lot of code that could be included

I remember 2 years ago someone proposed adding stream processing in datafusion and PRs followed. But IMO stream processing is an entirely different beast, some people could use the sql engine of df for it though. There are rust projects like Arroyo