import * as inspector from 'inspector';
import * as stream from 'stream';
import { Stopwatch } from '../helpers';
export type CpuProfileResult = inspector.Profiler.Profile;
export interface ProfilerInstance<TStopResult = void> {
    start: () => Promise<void>;
    stop: () => Promise<TStopResult>;
    dispose: () => Promise<void>;
    session: inspector.Session;
    sessionType: 'cpu' | 'memory';
    stopwatch: Stopwatch;
}
/**
 * Connects and enables a new `inspector` session, then starts an internal v8 CPU profiling process.
 * @returns A function to stop the profiling, and return the CPU profile result object.
 * The result object can be used to create a `.cpuprofile` file using JSON.stringify.
 * Use VSCode or Chrome's 'DevTools for Node' (under chrome://inspect) to visualize the `.cpuprofile` file.
 * @param samplingInterval - Optionally set sampling interval in microseconds, default is 1000 microseconds.
 */
export declare function initCpuProfiling(samplingInterval?: number): ProfilerInstance<CpuProfileResult>;
/**
 * Connects and enables a new `inspector` session, then creates an internal v8 Heap profiler snapshot.
 * @param outputStream - An output stream that heap snapshot chunks are written to.
 * The result stream can be used to create a `.heapsnapshot` file.
 * Use Chrome's 'DevTools for Node' (under chrome://inspect) to visualize the `.heapsnapshot` file.
 */
export declare function initHeapSnapshot(outputStream: stream.Writable): ProfilerInstance<{
    totalSnapshotByteSize: number;
}>;