import type { RetryBudgetConfig } from "./types.js";
export interface RetryBudgetState {
    available: boolean;
    failureRate: number;
    failures: number;
    samples: number;
    tripped: boolean;
    windowMs: number;
}
export declare class RetryBudget {
    private readonly window;
    private windowStart;
    private failures;
    private tripped;
    private readonly now;
    private readonly windowMs;
    private readonly maxSamples;
    private readonly minSamples;
    private readonly recoveryFailureRate;
    private readonly tripFailureRate;
    private lastNow?;
    constructor(now?: () => number, windowMs?: number, config?: Omit<RetryBudgetConfig, "window">);
    available(): boolean;
    observe(success: boolean): void;
    snapshot(): RetryBudgetState;
    private prune;
    private failureRate;
    private sampleCount;
    private removeOldest;
    private compactWindow;
    private remainsTripped;
    private refresh;
    private currentTime;
}