/**
 * Delivery watermark for channel replies.
 *
 * A progress notification should carry what just happened, not the whole
 * accumulated log replayed from the top. Tracking which events have already
 * been published is what turns a stream of ever-growing, mostly-identical
 * bodies into one short line per real event.
 *
 * The watermark is a set of event ids rather than an index because the event
 * buffer is trimmed from the front when it hits its cap, which would silently
 * shift any index-based mark.
 */
import type { ChannelRenderEvent } from './types.js';
/** Cap; keeps the watermark from growing without bound on a long run. */
export declare const MAX_DELIVERED_EVENT_IDS = 512;
export interface DeliveryWatermark {
    readonly deliveredEventIds: Set<string>;
}
/** Events not yet published, in buffer order. */
export declare function selectUndeliveredEvents(state: DeliveryWatermark, events: readonly ChannelRenderEvent[]): ChannelRenderEvent[];
/** Record events as published, dropping the oldest marks past the cap. */
export declare function markEventsDelivered(state: DeliveryWatermark, events: readonly ChannelRenderEvent[]): void;
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