export interface HarneryLogMetricsDelta {
    accepted?: number;
    encoded?: number;
    appended?: number;
    synced?: number;
    dropped?: number;
    coalesced?: number;
    sampled?: number;
    bytes_accepted?: number;
    bytes_appended?: number;
    bytes_dropped?: number;
    rotations?: number;
    failures?: Record<string, number>;
    append_latency_ms?: number;
    flush_latency_ms?: number;
    queue?: {
        bytes: number;
        capacity_bytes: number;
        peak_bytes: number;
        snapshot_at: string;
    };
}
export interface HarneryLogMetricsV1 {
    schema: "harnery.log-metrics/v1";
    generation: string;
    window_started_at: string;
    last_merge_at: string;
    last_successful_sink_at?: string;
    counters: {
        accepted: number;
        encoded: number;
        appended: number;
        synced: number;
        dropped: number;
        coalesced: number;
        sampled: number;
        bytes_accepted: number;
        bytes_appended: number;
        bytes_dropped: number;
        rotations: number;
    };
    failures: Record<string, number>;
    append_latency_histogram: readonly number[];
    flush_latency_histogram: readonly number[];
    queue?: HarneryLogMetricsDelta["queue"];
}
export declare class LogMetricsAccumulator {
    #private;
    increment<K extends keyof HarneryLogMetricsDelta>(key: K, amount?: number): void;
    failure(reason: string, amount?: number): void;
    observeQueue(bytes: number, capacityBytes: number, now: Date): void;
    observeLatency(kind: "append_latency_ms" | "flush_latency_ms", milliseconds: number): void;
    take(): HarneryLogMetricsDelta;
}
export declare function mergeMetricsSidecar(path: string, delta: HarneryLogMetricsDelta, now?: Date): {
    merged: boolean;
    generation_reset: boolean;
};
export declare function readMetricsSidecar(path: string): HarneryLogMetricsV1 | undefined;
//# sourceMappingURL=metrics.d.ts.map