/**
 * render-metrics.ts — Lightweight render performance tracking.
 *
 * Tracks min/mean/max render durations, request vs actual render counts,
 * active agents per render, time to first visible, and render rate.
 *
 * Use via environment variable PI_SUBAGENTS_LOG_LEVEL=debug to see slow render logs.
 */
export interface RenderMetricsSnapshot {
    label: string;
    renderCount: number;
    meanMs: number;
    minMs: number;
    maxMs: number;
    lastMs: number;
    requestedRenderCount: number;
    skippedRenderCount: number;
    requestToActualRatio: number;
    activeAgentCount: number;
    activeAgentMin: number;
    activeAgentMax: number;
    activeAgentMean: number;
    firstRenderTimestamp: number;
    firstSpawnTimestamp: number;
    timeToFirstVisibleMs: number;
    startedAt: number;
    elapsedMs: number;
    rendersPerSecond: number;
    rendersPerMinute: number;
}
export declare class RenderMetrics {
    private readonly label;
    private readonly slowThresholdMs;
    private renderCount;
    private totalRenderTime;
    private maxRenderTime;
    private minRenderTime;
    private lastDurationMs;
    private requestedRenderCount;
    private activeAgentCount;
    private activeAgentTotal;
    private activeAgentMin;
    private activeAgentMax;
    private firstRenderTimestamp;
    private firstSpawnTimestamp;
    private startedAt;
    constructor(label: string, slowThresholdMs?: number);
    /**
     * Record a requested render (before debounce/dirty-check filtering).
     * Returns the net requested count.
     */
    recordRequested(): number;
    /**
     * Record an actual render execution.
     *
     * @param durationMs - How long the render took.
     * @param activeAgents - How many agents were active at render time.
     * @returns true if the render was logged as slow.
     */
    record(durationMs: number, activeAgents?: number): boolean;
    /** Set the spawn timestamp for time-to-first-visible calculation. */
    setFirstSpawnTimestamp(ts: number): void;
    /** Reset all counters. */
    reset(): void;
    /** Get a snapshot of current metrics. */
    snapshot(): RenderMetricsSnapshot;
    /** Number of renders skipped due to debounce/dirty-check. */
    get skippedCount(): number;
    get mean(): number;
    get count(): number;
    get max(): number;
    get min(): number;
    get last(): number;
    get requestedCount(): number;
}