/**
 * A helper function that checks the metadata version / runtime version in intervals.
 * If a change is detected, an appropriate callback is executed.
 *
 * @param opts.metadata Options to restart upon metadata version change.
 * @param opts.runtime Options to restart upon runtime hash change.
 * @param opts.log Optional function to log the output.
 * @param opts.checkIntervalSeconds How often to check for changes. 10 minutes by default.
 * @returns A function to stop and cleanup the restarter.
 *
 * @example
 * runtimeRestarter({
 *   metadata: {
 *     getMetadataVersion: async () => (await api.rpc.state.getMetadata()).version.toString(),
 *     onMetadataChange: () => process.exit(1),
 *   },
 *   runtime: {
 *     getRuntimeVersionHash: async () => (await api.rpc.state.getRuntimeVersion()).hash.toString(),
 *     onRuntimeChange: () => process.exit(1),
 *   }
 *   log: (msg) => console.log(msg)
 * })
 */
export declare function runtimeRestarter(opts: {
    metadata?: {
        getMetadataVersion: () => Promise<string>;
        onMetadataChange: () => void | Promise<void>;
    };
    runtime?: {
        getRuntimeVersionHash: () => Promise<string>;
        onRuntimeChange: () => void | Promise<void>;
    };
    log?: (msg: string) => void;
    checkIntervalSeconds?: number;
}): () => void;