With 3.4 rust support was announced, but I couldn’t find any documentation on how to get started with rust for sailfish. I understand that probably many things are not yet figured out or subject to change.  There is whisperfish, which uses rust and Actix. Asides from that there should be gecko/mozilla for which the rust support was introduced (haven’t found the place where this is build yet).  Any hints, samples, etc. are welcome