/** Request payload for start. */
export declare function startRequest(requestId: string): void;
/** Starts timer. */
export declare function startTimer(label: string, parent?: string): () => void;
/** Time async. */
export declare function timeAsync<T>(label: string, fn: () => Promise<T>, parent?: string): Promise<T>;
/** Request payload for end. */
export declare function endRequest(requestId: string): void;
/** Check whether request performance timing is enabled. */
export declare function isEnabled(): boolean;
/**
 * Test-only: override the VERYFRONT_PERF gate and clear tracked state, so a
 * test can prove a request path releases its timing entry. Pass `undefined`
 * to restore lazy environment detection.
 */
export declare function __resetPerfTimerForTests(enabled?: boolean): void;
/** Test-only: ids of requests whose timing state was started but never ended. */
export declare function __trackedRequestIdsForTests(): string[];
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