Function open_with_eviction_summary 

pub fn open_with_eviction_summary(
    workspace: &Path,
    session_id: &str,
    max_events: usize,
    eviction_summary_hook: EvictionSummaryHook,
) -> Result<SessionEventLog, SessionStoreError>

Open a session log with a callback that persists summaries before cap eviction. A callback failure leaves the canonical event log unchanged.