import { IConfig } from '../TYPES/Config';
/**
 * Fetches the headers from the provided security master URL without retrieving the entire file.
 *
 * This function uses a 'HEAD' request to fetch only the headers of the file. It helps in
 * checking if the file has been modified or not by comparing the content hash from the headers.
 *
 * @param secMasterURL The URL of the security master data.
 * @returns The headers of the response, or null if an error occurs.
 */
export declare const fetchOnlyHeaders: (secMasterURL: string) => Promise<Headers | null>;
/**
 * Fetches the security master data from the provided URL, checks the file's content hash,
 * and updates the cache if the file content has changed.
 *
 * If the content hash is the same and the response is already cached, it returns the cached response.
 * Otherwise, it fetches the new data, updates the cache, creates indexes, and sends the data back to the main thread.
 *
 * @param secMasterURL The URL to fetch the security master data.
 * @param config Configuration options for indexing and handling the data.
 * @returns Void
 */
export declare const fetchSecurityMaster: (secMasterURL: string, config: IConfig) => Promise<void>;