/**
 * How a signal's name and data ride inside one string.
 *
 * `SYNC_SIGNAL` reuses the sync frame's single payload field, so the app's name
 * for the signal and whatever it sends with it have to share it. A two-key JSON
 * object is the whole format: `{"n":"file.sending","d":"photo"}`.
 *
 * Short keys on purpose. A signal is capped at two kilobytes by the relay, and
 * spending eight of them on the word "name" would be spending somebody else's
 * budget.
 *
 * The relay never parses this. Only the two ends do, which is what keeps the
 * platform blind to what an app's signals mean.
 */
/**
 * Built by hand rather than from an object, so the two keys always come out in
 * the same order. An object's key order is its own business, and a format that
 * depends on it is a format that differs between platforms.
 */
export declare function encodeSignal(name: string, data: string): string;
/**
 * Reads a signal back, or null when it is not one of ours.
 *
 * A signal from a newer app that carries something this one has never heard of
 * still reads as a name and some data, because nothing here interprets either.
 */
export declare function decodeSignal(payload: string): {
    name: string;
    data: string;
} | null;