less configuration. more reliable. less pure p2p (iroh uses relays)

ah very sorry, I can see how this isn't all that clear. In the comment you've mentioned when I say "custom protocol" I mean a custom QUIC ALPNs: https://datatracker.ietf.org/doc/html/rfc7301

When we talk to mainline it's for discovery, which is separate from iroh connections, which always uses QUIC. Specifically: our fork of quinn, an implementation of QUIC in rust. Iroh is tightly coupled to quinn, and isn't swappable. Getting no_std support for us basically boils down to "can we get quinn to support no_std?". For that, see: https://github.com/quinn-rs/quinn/issues/579

yep totally doable. You'd use iroh configured with mainline, Then write a custom protocol for the grpc bit: https://www.iroh.computer/docs/protocols/writing

We use this a bunch for writing rpc protocols on iroh: https://github.com/n0-computer/irpc , but there's no reason you couldn't write one with grpc.

keys are always ED25519, we use raw public key bytes, without prefixes.

Applications are more than welcome to use prefixes, but the use of ED25519 is not configurable

Yeah, no_std is going to be very hard. We need a no_std implementation of QUIC that can be wielded by mere mortals first, which I don't think we'll be able to start on for at least a year.

Right now we can get down to an ESP32, which we think is a decent start.