Solution: upgrade mio to 0.8.3 See the dependency tree below (`cargo audit`): ``` Crate: net2 Version: 0.2.37 Warning: unmaintained Title: `net2` crate has been deprecated; use `socket2` instead Date: 2020-05-01 ID: RUSTSEC-2020-0016 URL: https://rustsec.org/advisories/RUSTSEC-2020-0016 Dependency tree: net2 0.2.37 ├── miow 0.2.2 │ └── mio 0.6.23 │ ├── notify 4.0.17 │ │ └── tp-note 1.17.0 │ └── mio-extras 2.0.6 │ └── notify 4.0.17 └── mio 0.6.23 ```