pub fn with_var<K, V, F, R>(key: K, value: Option<V>, closure: F) -> Rwhere
K: AsRef<OsStr> + Clone + Eq + Hash,
V: AsRef<OsStr> + Clone,
F: FnOnce() -> R,Expand description
Sets a single environment variable for the duration of the closure.
The previous value is restored when the closure completes or panics, before unwinding the panic.
If value is set to None, then the environment variable is unset.