How to build variants in parallel (different python version)

[wenjuno]

In the documentation of building Python package with compiled extensions (https://rattler.build/latest/tutorials/python/#a-python-package-with-compiled-extensions), it shows the recipe for building numpy for different Python version using variants. But it will build different variant sequentially. The time can add up quickly when there are many variants and/or the build time for each variant is long. I would love to build different variants in parallel for faster CI pipeline. I find that when I don't use variants but rather pass the Python version as environment variable, the package name (the build string specifically) does not contain the Python version specific part (e.g. py311 for Python 3.11 build), leading to all packages having the same filename. What is the best way to parallelize the build for different Python versions (or variants in general)? Thanks.