Function classify_attempt 

pub fn classify_attempt(
    policy: &RetryPolicy,
    attempt: u32,
    outcome: &SettlementRoutingInput,
) -> RetryDecision

Classify one attempt’s outcome under the supplied policy.

attempt is the zero-indexed retry counter for the current observation. Pass 0 on the first failure; on the next failure pass 1, etc. The returned RetryDecision tells the caller whether to sleep and replay or to land a dead-letter row.

Permanent outcomes short-circuit and typed reasons are preserved.