Function canonical_key_min_width 

pub fn canonical_key_min_width() -> usize

Sweep the threshold without a rebuild: ATLAS_CANONICAL_KEY_MIN_WIDTH=<n> (VALUE-parsed; 0 = canonical at every width, a value above the widest batch = never). Unset or unparseable ⇒ CANONICAL_KEY_MIN_WIDTH. Parsed once per process, like dcut_width_cap.