export declare class StateTracker<T, K = string> extends Map<K, T> {
    protected readonly defaultValue?: T | undefined;
    protected readonly defaultState?: K | undefined;
    protected cachedState?: K;
    protected cachedValue?: T;
    private locked?;
    constructor(defaultValue?: T | undefined, defaultState?: K | undefined);
    set(key: K, value?: T): this;
    delete(key: K): boolean;
    /**
     * Pins `value` as the reported state until {@link unlock}, so a caller owning an ongoing
     * interaction is not overridden by others. Their updates are still recorded, so releasing the
     * lock resumes whichever state is current by then.
     */
    lock(key: K, value: T): void;
    /** Releases a lock; a no-op unless `key` is the lock holder, so one owner cannot release another's. */
    unlock(key: K): void;
    isLocked(): boolean;
    stateId(): K | undefined;
    stateValue(): T | undefined;
}
export declare class NonNullableStateTracker<T, K = string> extends StateTracker<T, K> {
    protected readonly defaultValue: T;
    protected readonly defaultState: K;
    constructor(defaultValue: T, defaultState: K);
    stateId(): K;
    stateValue(): T;
}