import { MomentoLoggerFactory } from '../../';
import { ExperimentalMetricsMiddleware } from './impl/experimental-metrics-middleware';
/**
 * This middleware enables per-request client-side metrics.  Metrics for each
 * request will be written to a CSV file; this file can be analyzed or shared
 * with Momento to diagnose performance issues.
 *
 * The metrics format is currently considered experimental; in a future release,
 * once the format is considered stable, this class will be renamed to remove
 * the Experimental prefix.
 *
 * WARNING: enabling this middleware may have minor performance implications,
 * so enable with caution.
 *
 * WARNING: depending on your request volume, the CSV file size may grow quickly;
 * neither sampling nor file compression / rotation are included at this time
 * (though they may be added in the future).
 *
 * See `advanced.ts` in the examples directory for an example of how to set up
 * your {Configuration} to enable this middleware.
 */
export declare class ExperimentalMetricsCsvMiddleware extends ExperimentalMetricsMiddleware {
    static numActiveRequests: number;
    private readonly csvPath;
    constructor(csvPath: string, loggerFactory: MomentoLoggerFactory);
}