/**
 * Asynchronous lock.
 * @example
 * ```javascript
 * // Usage example:
 * const lockObj = new AsyncLock();
 * await lockObj.lock();
 * try {
 *   // code
 * } finally {
 *   lockObj.unlock();
 * }
 * ```
 **/
export declare class AsyncLock {
    private _promise;
    private _resolve;
    constructor();
    /**
     * Lock code execution.
     * @example
     * ```javascript
     * await lockObj.lock();
     * ```
     **/
    lock(): Promise<void>;
    /**
     * Unlock code execution.
     * @example
     * ```javascript
     * lockObj.unlock();
     * ```
     **/
    unlock(): void;
}