import ResizeObserver from 'resize-observer-polyfill';
/**
 * Service class to send height information of the plug-in to COYO.
 */
export declare class HeightAdapter {
    private readonly srcId;
    private static readonly RES_SUBJECT;
    protected observer: ResizeObserver | null;
    /**
     * Creates a new instance of this class.
     *
     * @param srcId the plug-in source ID to use for requests
     * @returns the new instance
     */
    constructor(srcId: string);
    /**
     * Connects this adapter to the HTML element that matches the given selectors,
     * observes its height and sends throttled update messages to COYO.
     *
     * @param selectors the selectors to target the HTML element
     * @param throttle a small timeframe to throttle messages
     */
    connect(selectors: string, throttle: number): void;
    /**
     * Disconnects this adapter from all HTML elements.
     */
    disconnect(): void;
    private throttle;
}