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

This blog post details the process of implementing automatic server reloading in Rust using systemfd and listenfd, drawing parallels to similar mechanisms in Werkzeug and Flask. It discusses how to monitor file changes with tools like cargo watch and watchexec, and explains socket activation as a concept borrowed from systemd for passing file descriptors between processes. The author provides practical examples and recommendations for setting it up, also touching on improvements and potential integration within Rust frameworks.