Comment by syrusakbary

I think this showcases the other issue I commented a few years ago [1].

Pyodide and Cloudflare don't use the real network stack for http requests (they patched the functions to use JS `fetch` underneath). They also patched Python's async event loop to use JS event loop.

This has a major downside: incompatibility issues. JS event loop is preemptive (async functions get called regardless of you calling await on them) while Python is lazy (async functions only execute when you await them).

In my belief, the network semantics should be preserved. When the behavior differs issues start arising.

[1] https://news.ycombinator.com/item?id=39907240