import type { Profiler } from './profiler.js';
import type { ProfileSource } from './types.js';
/** Configuration shared by editor and standalone Play browser hosts. */
export interface UserTimingProfilerOptions {
    /** Global flag that enables marks. Defaults to the harness diagnostic flag. */
    readonly diagnosticsKey?: string;
    /** Stable id written into the optional Profiler capture projection. */
    readonly captureId?: string;
    /** Host callback invoked after an owner phase closes. */
    readonly onPhaseEnd?: (phase: {
        readonly source: ProfileSource;
        readonly phase: string;
    }) => void;
}
/**
 * Creates a zero-cost-while-disabled browser projection of the engine Profiler.
 *
 * The engine frame loop remains the phase owner. This adapter only translates
 * the already-open phases to User Timing marks when a host explicitly enables
 * the diagnostic flag before app creation. Normal game/editor frames therefore
 * do not allocate a profiler or call performance.mark().
 */
export declare function createUserTimingProfiler(options?: UserTimingProfilerOptions): Profiler | undefined;
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