import type { Log } from '@apify/log';
import type { Configuration } from '../configuration';
import type { LoadSignal, LoadSnapshot } from './load_signal';
import type { SystemInfo } from './system_status';
export interface MemorySnapshot extends LoadSnapshot {
    usedBytes?: number;
}
export interface MemoryLoadSignalOptions {
    maxUsedMemoryRatio?: number;
    overloadedRatio?: number;
    snapshotHistoryMillis?: number;
    config: Configuration;
    log?: Log;
}
/**
 * Tracks memory usage via `SYSTEM_INFO` events and reports overload when
 * the used-to-available memory ratio exceeds a threshold.
 */
export declare class MemoryLoadSignal implements LoadSignal {
    readonly name = "memInfo";
    readonly overloadedRatio: number;
    private readonly store;
    private readonly config;
    private readonly events;
    private readonly log;
    private readonly maxUsedMemoryRatio;
    private maxMemoryRatio;
    private maxMemoryBytes;
    private lastLoggedCriticalMemoryOverloadAt;
    constructor(options: MemoryLoadSignalOptions);
    start(): Promise<void>;
    stop(): Promise<void>;
    getSample(sampleDurationMillis?: number): MemorySnapshot[];
    /**
     * Returns typed memory snapshots for backward compatibility with `Snapshotter`.
     */
    getMemorySnapshots(): MemorySnapshot[];
    /** @internal */
    _onSystemInfo(systemInfo: SystemInfo): void;
    /** @internal */
    _memoryOverloadWarning(systemInfo: SystemInfo, maxMemoryBytes?: number): void;
    private _getTotalMemoryBytes;
}