type Snapshot = {
    el: Element;
    rect: DOMRect;
    clone: HTMLElement;
    mountInFlow: () => void;
    mountFixed: () => void;
};
type Listener = (s: Snapshot) => void;
export declare function onBeforeDisconnect(el: Element, fn: Listener, opts?: {
    once?: boolean;
}): (immediate?: boolean) => void;
export {};