/**
 * Tracks metrics changes and returns only changed values
 */
export default class MetricsDiffer {
    private previousMetrics;
    /**
     * Get changed metrics by comparing current with previous
     * @param currentMetrics - Current metrics object
     * @returns Only the metrics that have changed since last call
     */
    getChangedMetrics(currentMetrics: object): object;
    /**
     * Reset the differ (clear previous metrics)
     */
    reset(): void;
    /**
     * Get the previous metrics snapshot (for testing/debugging)
     */
    getPreviousMetrics(): object | null;
}