/**
 * Pending Queries
 *
 * Manages async query state for the "one moment please" acknowledgment pattern.
 * When a query is processing in the background, the pending promise is stored
 * here and resolved when processing completes.
 */
export interface PendingQuery {
    speechResult: string;
    promise: Promise<{
        twiml: string;
    }>;
    resolve: (value: {
        twiml: string;
    }) => void;
    createdAt: number;
}
export type PendingQueryInput = Omit<PendingQuery, "createdAt">;
export declare function setPending(phoneNumber: string, query: PendingQueryInput): void;
export declare function getPending(phoneNumber: string): PendingQuery | undefined;
export declare function deletePending(phoneNumber: string): void;
/**
 * Delete pending queries older than `ttlMs`. A caller (Twilio hanging up
 * before requesting /call/answer, a client that never follows the redirect)
 * can leave an entry that nothing ever resolves or deletes; without a sweep
 * it — and its unresolved promise — would leak for the process lifetime.
 */
export declare function sweepPending(ttlMs: number): void;