Function sink 

pub fn sink(
    reporters: Vec<Box<dyn Reporter>>,
    redactions: Redactions,
) -> EventSink

Fan a reporter stack out as an EventSink (thread-safe: scenario threads share the sink). Redaction happens here, once, before fan-out — every reporter (console, JSONL record, future sinks) sees only redacted events, so the invariant does not depend on each leaf remembering to redact.