Just curious if you looked at Apache Airflow as the integration functionality and pipeline / DAG configuration approaches are similar and it's also done in Python.

https://github.com/apache/airflow

The Nim language is new to me. What was the experience like implementing a framework in it?

You can trivially define a worker pool or arbitrary size and pipe a stream of values through your function using multiple cores, avoiding GIL issues.

If you have something which scales to multiple machines just use celery or redis streams.

Small bug in the example code? I think this:

    return even % 2 == 0

    return number % 2 == 0