zengfr/stepchain ? reverse-engineered prompt

Build me a Java workflow pipeline library like the one in this repo, with a Spring Boot starter so I can plug it into an app easily.

I want to define a business flow as a chain of small processors, then run them in order or in parallel. It should support nested flows, branching with if else and switch style logic, loops, and the ability to turn steps on or off by config. I also want a simple way to create processors from functions or lambdas, and to combine processors into reusable chains.

Please include a small demo that shows a request going through several steps and updating shared context data, plus a Spring Boot example if possible. It should feel easy to use for normal business processing, not just a framework for experts. If you need to check current library or Spring Boot docs for compatibility details, look them up online.