/** A one-use document-bound reservation for a deferred overlay's activation order. */
export type OverlayOrderReservation=(document:Document)=>number|undefined;
/** Reserves shared ordering before a first-open runtime starts loading. */
export declare function reserveOverlayOrder(document:Document):OverlayOrderReservation;
/** Consumes a matching reservation once; ordinary activation or adoption receives a new order. */
export declare function takeOverlayOrder(document:Document,reservation?:OverlayOrderReservation):number;