export declare class MetricStreamer {
    private sendFn;
    private sessionId;
    private visitorId;
    private deviceSent;
    lastPageTs: string | Date;
    private entryTime;
    private maxScrollDepth;
    private scrollHandler;
    private heartbeatTimer;
    private currentPage;
    private boundStorageHandler;
    constructor(sendFn: (payload: Record<string, unknown>) => void);
    private refreshSession;
    private handleStorageSync;
    trackPageview(page?: string, referrer?: string): void;
    private sendHeartbeat;
    private sendFarewell;
    private startHeartbeat;
    private bindUnload;
    private bindStorageSync;
    private collectDeviceInfo;
    private getUtm;
    private trackScroll;
    destroy(): void;
}