/**
 * A set of key value pairs that supports
 * fast queries for both keys and values.
 */
export declare class PairSet<K, V> {
    #private;
    add(key: K, value: V): void;
    delete(key: K, value: V): void;
    deleteKey(key: K): void;
    getKeys(value: V): ReadonlySet<K> | undefined;
}