Function read_event_window 

pub fn read_event_window(
    after: u64,
    limit: usize,
    level: Option<&str>,
    event_prefixes: &[&str],
) -> Option<EventWindow>

Drain the ring into an EventWindow for a cursor read. Returns the entries with seq > after, capped at limit (oldest-first), each with its seq folded into the emitted line object. level/event_prefixes are optional server-side filters — a cheap prefix match over the held lines, not a query engine. None when no ring is installed (the resource 404s at the server).