Function assertion_sometimes_each 

pub fn assertion_sometimes_each(
    msg: &str,
    keys: &[(&str, i64)],
    quality: &[(&str, i64)],
)

Backing function for per-value bucketed assertions.

Each unique combination of identity key values creates one bucket. Signals discovery on first hit. Optional quality keys re-signal when the packed quality score improves (CAS loop on best_score).

This is a no-op if EachBucket memory is not initialized.