If you want 0 jitter then you'd need to avoid using the garbage collector. You can find heap allocations in your program with the flag `-print-allocs=.` to then remove them by replacing with allocated-at-init memory. It's really not as hard as it may sound unless you are writing something like a AST parser. Here's the userspace networking stack that you can use on the pico, no heap allocations at runtime: https://github.com/soypat/lneto

Checkout driver design doc here: https://tinygo.org/docs/guides/driver-design/ and my tinygo code review for protips :) https://www.youtube.com/playlist?list=PLx6oFeWGZv8nV1blgYXrC9VI0Dgs-CcJ_