/** Stable User Timing measure names emitted by VectoJS instrumentation. */
export declare const VECTO_USER_TIMING: {
    readonly scene: {
        readonly transform: 'vecto:scene:transform';
        readonly drawWalk: 'vecto:scene:draw-walk';
        readonly entityPaint: 'vecto:scene:entity-paint';
        readonly flush: 'vecto:scene:flush';
        readonly a11ySync: 'vecto:scene:a11y-sync';
    };
    readonly markdown: {
        readonly parse: 'vecto:markdown:parse';
    };
};
interface TimingPerformance {
    now(): number;
    mark(name: string, options?: {
        startTime?: number;
    }): unknown;
    measure(name: string, startMark: string, endMark: string): unknown;
    clearMarks?(name?: string): void;
}
/** Opaque handle for one enabled User Timing interval. */
export interface VectoUserTimingSpan {
    readonly name: string;
    readonly startMark: string;
    readonly endMark: string;
    readonly performance: TimingPerformance;
}
/**
 * Begin a User Timing interval when the host implements marks and measures.
 * Returns `null` instead of making optional profiling a runtime requirement.
 */
export declare function beginVectoUserTiming(name: string): VectoUserTimingSpan | null;
/** Finish a span and release its uniquely named marks. */
export declare function endVectoUserTiming(span: VectoUserTimingSpan | null): void;
/**
 * Emit one measure for a duration accumulated from disjoint calls.
 *
 * The marks are anchored at the current time with the measured duration ending
 * there. This keeps one entry per frame while still reporting the sum of every
 * entity's paint call instead of instrumenting every entity individually.
 */
export declare function measureVectoUserTiming(name: string, durationMs: number): void;
export {};