Macro detail 

macro_rules! detail {
    ($($arg:tt)*) => { ... };
}

Formats runtime diagnostic detail in debug builds and strips it in release builds.

In release builds the format arguments are not evaluated — any side effects in the argument expressions are skipped.

let detail = redacted_error::detail!("addr={}", "127.0.0.1");
assert_eq!(detail, "addr=127.0.0.1");