import { RolloutConfig } from './types';
/**
 * Deterministically checks if a given key falls within a rollout percentage.
 *
 * @param key The stickiness key (e.g. userId)
 * @param config Rollout configuration including percentage, salt, and bucket max
 * @returns true if the key hashes to a bucket < percentage
 */
export declare function isInRollout(key: string | undefined, config: RolloutConfig | undefined): boolean;
/**
 * Returns a deterministic bucket number (default 0-99) for a given key and salt.
 * Uses MurmurHash3 (32-bit).
 */
export declare function getHashBucket(key: string, salt?: string, buckets?: number): number;