import { EventEmitter } from 'node:events';
import Optional from './Optional';
export default class StopWatch extends EventEmitter {
    private readonly rounds;
    private totalTimePaused;
    private pauseStartTime?;
    private threshold?;
    private startTime;
    constructor();
    /**
     * Fixes the elapsed time when the stopwatch is paused.
     */
    private fixPausedTime;
    /**
     * Records a round by calculating the lap time and emitting a 'round' event.
     */
    round(): void;
    /**
     * Resets the stopwatch to its initial state and emits a 'reset' event.
     */
    reset(): void;
    /**
     * Returns the elapsed time in milliseconds.
     * @returns The elapsed time in milliseconds.
     */
    time(): number;
    /**
     * Returns the recorded rounds.
     * @returns An array of lap times for each round.
     */
    getRounds(): number[];
    /**
     * Pauses the stopwatch and emits a 'pause' event.
     */
    pause(): void;
    /**
     * Resumes the stopwatch if paused and emits a 'resume' event.
     */
    resume(): void;
    formatLapTime(lapTime: number): string;
    getAverageLapTime(): number;
    getMaximumLapTime(): number;
    getMinimumLapTime(): number;
    setLapTimeThreshold(threshold: number): void;
    getLapTimeAtIndex(index: number): Optional<number>;
    /**
     * Adds an event listener for the 'round' event.
     * @param callback - The callback function to be called when a 'round' event is emitted.
     */
    onRound(callback: (lapTime: number) => void): void;
}