/**
 * Lightweight OTel-compatible tracing for Zeta crawler.
 *
 * Emits spans as structured JSON logs compatible with OpenTelemetry format.
 * Drop-in upgrade path: replace this module with @opentelemetry/sdk-node when needed.
 *
 * Usage:
 *   const span = startSpan('crawl.url', { url, engine });
 *   // ... do work ...
 *   endSpan(span, { screensFound: 3 });
 */
export interface Span {
    traceId: string;
    spanId: string;
    parentSpanId?: string;
    name: string;
    startTimeMs: number;
    attributes: Record<string, string | number | boolean>;
}
export interface FinishedSpan extends Span {
    endTimeMs: number;
    durationMs: number;
    status: 'ok' | 'error';
    error?: string;
}
/** Start a new span. If a trace is already active, the new span is a child. */
export declare function startSpan(name: string, attributes?: Record<string, string | number | boolean>): Span;
/** End a span and emit it as a structured log line. */
export declare function endSpan(span: Span, extraAttributes?: Record<string, string | number | boolean>, error?: Error): FinishedSpan;
/** Convenience: wrap an async function in a span. */
export declare function withSpan<T>(name: string, attributes: Record<string, string | number | boolean>, fn: (span: Span) => Promise<T>): Promise<T>;
export declare function increment(metric: string, value?: number, tags?: Record<string, string>): void;
/** Flush counters as a structured log — call periodically (e.g. at job end). */
export declare function flushMetrics(): Record<string, number>;