/**
 * Ensures a callback takes at least a minimum amount of time to execute.
 * This helps prevent timing attacks where an attacker measures response times
 * to infer sensitive information (e.g., user enumeration via password reset).
 *
 * @example
 * ```ts
 * // Password reset: both paths (user exists or not) take same minimum time
 * return safeTiming(200, async () => {
 *   const user = await User.findBy('email', email)
 *   if (user) await sendResetEmail(user)
 *   return { message: 'If this email exists, you will receive a reset link.' }
 * })
 *
 * // API token verification: skip the delay on valid token
 * return safeTiming(200, async (timing) => {
 *   const token = await Token.findBy('value', request.header('x-api-key'))
 *   if (token) {
 *     timing.returnEarly()
 *     return token.owner
 *   }
 *   throw new UnauthorizedException()
 * })
 * ```
 */
export declare function safeTiming<T>(minimumMs: number, callback: (timing: {
    returnEarly(): void;
}) => Promise<T>): Promise<T>;