Function access_log_line 

pub fn access_log_line(
    method: &str,
    path: &str,
    status: u16,
    correlation_id: &str,
    dur: Duration,
) -> String

A structured, SECRET-SAFE request log line: method, path, status, correlation id, and duration — and never an arbitrary request header VALUE (so a secret in Authorization/Cookie can never leak into logs). Returned as a string so the caller decides the sink (both tiers format identically).