Function flush_codex_turn_usage

src/sessions/transcript_backfill.rs:348–364

Attach a finished Codex turn's summed usage to its assistant line's facts, merging additively when several flushes land on the same line.

(
    facts: &mut HashMap<i64, LineFacts>,
    assistant_offset: Option<i64>,
    turn_usage: &mut CodexTurnUsage,
)

/// Attach a finished Codex turn's summed usage to its assistant line's facts,
/// merging additively when several flushes land on the same line.
fn flush_codex_turn_usage(
    facts: &mut HashMap<i64, LineFacts>,
    assistant_offset: Option<i64>,
    turn_usage: &mut CodexTurnUsage,
) {
    let Some(usage) = turn_usage.take() else {
        return;
    };
    let Some(offset) = assistant_offset else {
        return;
    };
    let entry = facts.entry(offset).or_default();
    match entry.usage.as_mut() {
        Some(existing) => merge_usage_counters(existing, &usage),
        None => entry.usage = Some(usage),
    }
}

/// Per-provider timestamp derivation, mirroring each source's live ingest.
fn derive_timestamp(provider: &str, record: &Value, carry: &mut TimestampCarry) -> Option<i64> {