export type PrinterHttpEndpoint = {
    printerIp: string;
    devId: string;
    useHttps: boolean;
};
/** Stable key for the Epson `service.cgi` endpoint (same IP + devId share one gate). */
export declare function buildPrinterHttpGateKey({ printerIp, devId, useHttps }: PrinterHttpEndpoint): string;
/**
 * Serializes every HTTP POST to the same printer endpoint.
 * Epson `service.cgi` accepts one request at a time; overlapping print jobs and
 * heartbeats otherwise produce short-lived canceled fetches in the browser.
 */
export declare function runSerializedPrinterHttp<T>(gateKey: string, operation: () => Promise<T>): Promise<T>;