/**
 * Forces garbage collection. A single pass is not enough to settle the heap;
 * phase-0 measurements used 3 passes separated by event-loop ticks so that
 * finalizers and pending callbacks can release references between passes.
 * Returns false when the process was not started with `--expose-gc`.
 */
export declare function forceGc(passes?: number): Promise<boolean>;
export type HeapSample = {
    gcExposed: boolean;
    heapUsed: number;
    rss: number;
    external: number;
    arrayBuffers: number;
    /**
     * Identity of the process that produced this sample. Optional in the type so
     * fixtures stay readable; the wire schema in `control-client.ts` requires it,
     * so a real sample always carries it.
     */
    pid?: number;
    ppid?: number;
    argv?: readonly string[];
    cwd?: string;
    /**
     * HTTP requests this process has served since boot, counted by the probe in
     * `bootstrap.ts`. Recorded as evidence of how much traffic reached the
     * process behind a reading, not checked anywhere: a clustered server counts
     * in whichever process took the connection. `undefined` when the probe was
     * not installed.
     */
    servedRequests?: number | undefined;
};
/** Where `bootstrap.ts` publishes the served-request count. */
export declare const requestProbe: typeof globalThis & {
    __nextLeakServedRequests?: number;
};
export type ControlServerOptions = {
    /** Directory where heap snapshots are written. */
    snapshotDir: string;
    /** Injectable for tests; defaults to `v8.writeHeapSnapshot`. */
    writeSnapshot?: (file: string) => string;
};
export type ControlServer = {
    port: number;
    close: () => Promise<void>;
};
/**
 * Internal control channel booted inside the measured app's process.
 *
 * - `GET /gc` — force GC, respond with a memory sample.
 * - `GET /mem` — respond with a memory sample WITHOUT collecting.
 * - `GET /snapshot?name=<label>` — force GC, write `<label>.heapsnapshot`
 *   into `snapshotDir`, respond `{ file, sample }` only once fully written.
 */
export declare function startControlServer(options: ControlServerOptions): Promise<ControlServer>;