import { Metric } from '../index';
import { Histogram } from './index';
export declare class Timing extends Histogram implements Metric {
    private ongoing?;
    _init(options?: Histogram.Options): void;
    begin(): Timing.Stopwatch;
    /**
     * Usually call `Stopwatch.end()` rather than this method.
     */
    end(stopwatch: Timing.Stopwatch): void;
    _read(): Histogram.Fields | undefined;
    protected init(): boolean;
}
export declare namespace Timing {
    class Stopwatch {
        private readonly owner;
        private readonly startTime;
        constructor(owner: Timing);
        end(): void;
        /**
         * Return elapsed milliseconds since begin.
         */
        elapse(): number;
    }
}