import type { BroadcastState } from "./types.js";
/**
 * Generic LRU cache for aggregate state objects.
 *
 * Keyed by stream ID. Each entry stores the full state (with `_v` from the
 * event store). Used as the "previous state" baseline for computing patches,
 * and as the fast path for reconnects.
 *
 * The cache is shared between the broadcast hot path and read queries.
 * Projections should maintain their own cache to avoid double-apply bugs.
 */
export declare class StateCache<S extends BroadcastState = BroadcastState> {
    private cache;
    private maxSize;
    constructor(maxSize?: number);
    /** Get a cached state, promoting it to MRU position. */
    get(key: string): S | undefined;
    /** Set a cached state, evicting the LRU entry if at capacity. */
    set(key: string, state: S): void;
    /** Remove a cached entry. */
    delete(key: string): void;
    /** Check if a key exists in the cache. */
    has(key: string): boolean;
    /** Current number of cached entries. */
    get size(): number;
    /** Direct access to the underlying map (for iteration). */
    entries(): IterableIterator<[string, S]>;
}
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