/**
 * @file Feature-flag check — `isPerfEnabled()` returns true when `DEBUG=perf`
 *   is set in the environment. Every recording entry (timer / checkpoint /
 *   memory) bails out cheaply when this is false.
 */
/**
 * Check if performance tracking is enabled.
 *
 * Reads `DEBUG` through `getEnvValue` so tests can mock the value via
 * `setEnv('DEBUG', 'perf')` from `@socketsecurity/lib/env/rewire` without
 * mutating `process.env`.
 */
export declare function isPerfEnabled(): boolean;
