/**
 * Await-compatible older-history result with a causal commit receipt.
 *
 * `committed` flips synchronously before the accepted older window is exposed
 * to React. Returning this exact object preserves the receipt directly;
 * synchronous wrappers that discard it remain supported through receipt
 * capture, while replacing it asynchronously with a plain promise does not.
 */
export type OlderHistoryLoadReceipt = Promise<boolean> & {
    readonly committed: boolean;
    readonly tailPreserved?: boolean;
};
/**
 * Source-compatible public callback accepted by MessageTimeline.
 *
 * The callback historically returned `void`, which permits consumers to
 * return any synchronous value or promise. Receipt-aware loaders opt into the
 * stronger runtime contract by returning (or synchronously creating through a
 * wrapper) an {@link OlderHistoryLoadReceipt}.
 */
export type OlderHistoryLoader = () => unknown;
type OlderHistoryReceiptCapture = (receipt: OlderHistoryLoadReceipt) => void;
/** Bind a receipt before a synchronous forwarding stack can publish state. */
export declare function invokeOlderHistoryLoaderWithReceiptCapture(load: OlderHistoryLoader, capture: OlderHistoryReceiptCapture, preserveTail?: boolean): unknown;
/**
 * Build an await-compatible older-history receipt for custom timeline hosts.
 * Call `markCommitted` immediately before publishing an accepted older window.
 */
export declare function createOlderHistoryLoadReceipt(load: (markCommitted: () => void, preserveTail: boolean, markTailPreserved: () => void) => boolean | Promise<boolean>): OlderHistoryLoadReceipt;
export {};