Automatic Server Reloading in Rust on change: What is listenfd/systemfd?

from blog Armin Ronacher's Thoughts and Writings, | ↗ original
When I developed Werkzeug (and later Flask), the most important part of the developer experience for me was enabling fast, automatic reloading. Werkzeug (and with it Flask), this is achieved by using two procsses at all times. The parent process holds on to the file descriptor of the socket on which the server listens, and a subprocess picks up...