export declare class ReferenceCircuitBreaker {
    private readonly failureThreshold;
    private readonly cooldownMs;
    private readonly circuits;
    private readonly headUnsupported;
    constructor(failureThreshold?: number, cooldownMs?: number);
    isOpen(host: string): boolean;
    recordSuccess(host: string): void;
    recordFailure(host: string): void;
    supportsHead(host: string | null): boolean;
    markHeadUnsupported(host: string | null): void;
    reset(): void;
}
//# sourceMappingURL=reference-circuit-breaker.d.ts.map