What sort of architecture are you envisioning where you'd need HTTP3 and Rust can't build for it?

Once you get a microcontroller fast enough to handle Http3, you are talking about well known platforms (such as ARM, MIPS, x86). All of which are supported by Rust and LLVM.

https://doc.rust-lang.org/nightly/rustc/platform-support.htm...

Keeping in mind that I needed to write code against node 0.13 because it was the last version of node supporting floating point emulation when there is no hardware fpu, I was surprised to learn what kind of trash is out there running the internet. There is list of supported architectures of the software in question and though I don't remember it in details, I'm sure that there were items in it that I couldn't find in the rust tables.

:) sounds like bcm4709. Funnily, rust wouldn't have a problem there, that's specifically a node problem because their JIT doesn't handle software FPUs. LLVM does.

I'm fairly confident in saying any place you can run any node version, you can run rust.

https://github.com/nxhack/openwrt-node-packages/issues/15

In this case the node had to run on Luxul routers, I don't remember the architecture.