The following actions uses node12 which is deprecated and will be forced to run on node16: actions/checkout@v2, actions-rs/cargo@v1. For more info: https://github.blog/changelog/2023-06-13-github-actions-all-actions-will-run-on-node16-instead-of-node12-by-default/

The following actions uses Node.js version which is deprecated and will be forced to run on node20: actions/checkout@v2, actions/cache@v3, actions/github-script@v6, actions-rs/cargo@v1. For more info: https://github.blog/changelog/2024-03-07-github-actions-all-actions-will-run-on-node20-instead-of-node16-by-default/

struct `AlwaysSubscriber` is never constructed

`muxado` (example "server" test) generated 1 warning