Bad file descriptor errors -- How are file descriptors stored in WASM module?

I've started getting `write error: Bad file descriptor` and `standard output: Bad file descriptor` (e.g. output of busybox's echo and base64).

I'm saving/resetting memory of WASM module to speed up launch time. Before it has worked like a charm. I'm also overriding `Module.stdout` to capture the module output.

What could be the reason? Thanks!

It's as if standard output file descriptor became "closed" somehow. How is the state of stdout stored?

Here is my code: https://github.com/busytex/busyide/blob/main/busybox.js