pub fn env(key: &str) -> Option<String>Expand description
An app-environment value, portably: the process environment on native targets, the page
URL’s query string on web-dom (where a browser sandbox has no process environment —
day launch --env K=V forwards each pair as a query parameter, docs/web.md). Prefer this
over std::env::var for anything a --env flag should be able to set on every target.