/// <reference types="node" />
/**
 * Incrementally updated statistics on a set of values.
 * @public
 */
export declare class Statistics {
    /** The number of decimal places to print in {@link Statistics.toString} */
    protected printFixedPrecision: number;
    /** Number of values observed. */
    samples: number;
    /** The maximum value observed. Initialized to `Number.NEGATIVE_INFINITY`. */
    max: number;
    /** The minimum value observed. Initialized to `Number.POSITIVE_INFINITY`. */
    min: number;
    /** The variance of the values observed. */
    variance: number;
    /** The standard deviation of the values observed. */
    stdev: number;
    /** The mean (average) of the values observed. */
    mean: number;
    /**
     * Incrementally track mean, stdev, min, max, of a sequence of values.
     * @param printFixedPrecision - The number of decimal places to print in
     * {@link Statistics.toString}.
     */
    constructor(
    /** The number of decimal places to print in {@link Statistics.toString} */
    printFixedPrecision?: number);
    /** @internal */
    clone(): Statistics & this;
    /**
     * Update statistics with a new value in the sequence.
     */
    update(value: number | undefined): void;
    /**
     * Print the mean of the observations seen, with the precision specified in
     * the constructor.
     */
    toString(): string;
}
export declare class ExponentiallyDecayingAverageValue {
    smoothingFactor: number;
    samples: number;
    value: number;
    constructor(smoothingFactor: number);
    update(n: number): void;
    toString(): number;
}
export declare function sleep(ms: number, cancel?: Promise<void>): Promise<unknown>;
export declare function streamToBuffer(s: NodeJS.ReadableStream): Promise<Buffer>;
export declare function chomp(s: string): string;
export declare const sum: (a: number[]) => number;
export declare function objectSize(obj?: {
    [key: string]: string;
}): number;
export declare function computeHttpResponseBytes(headers: {
    [key: string]: string;
}, opts?: {
    httpHeaders: boolean;
    min: number;
}): number;
export declare function hasExpired(date: string | number | undefined | null, retentionInDays: number): boolean;
export declare function roundTo100ms(n: number): number;
export declare const uuidv4Pattern = "[a-f0-9]{8}-[a-f0-9]{4}-4[a-f0-9]{3}-[89aAbB][a-f0-9]{3}-[a-f0-9]{12}";
export declare const GB: number;
export declare const MB: number;
export declare const KB: number;
export declare function f1(n: number): string;
export declare function f2(n: number): string;
export declare function keysOf<K extends string, O extends {
    [key in K]: any;
}>(obj: O): Array<keyof O>;
export declare function defined<T>(arg: T | undefined | null | void): arg is T;
export declare class MaxHeap {
    protected _heap: number[];
    get size(): number;
    clear(): void;
    peekMax(): number;
    insert(value: number): void;
    extractMax(): number;
    [Symbol.iterator](): IterableIterator<number>;
}
export declare class SmallestN<T = void> {
    protected _size: number;
    protected _heap: MaxHeap;
    protected _map: [number, T][];
    constructor(_size: number);
    update(key: number, value: T): void;
    protected shrink(): void;
    [Symbol.iterator](): IterableIterator<[number, T]>;
    entries(): () => IterableIterator<[number, T]>;
    keys(): number[];
    get size(): number;
    clear(): void;
    setSize(newSize: number): void;
}