// "Server" end of RPC
const { performRpc } = useRpc(session, {
  getUserLocation: rpc.json(async (payload: { highAccuracy: boolean }, data) => {
    const position = await new Promise<GeolocationPosition>((resolve, reject) => {
      navigator.geolocation.getCurrentPosition(resolve, reject, {
        enableHighAccuracy: payload.highAccuracy,
        timeout: data.responseTimeout * 1000,
      });
    });
    return {
      latitude: position.coords.latitude,
      longitude: position.coords.longitude,
    };
  }),
});

// "Client" end of RPC
const result = await performRpc(rpc.json<{ highAccuracy: boolean }, { latitude: number; longitude: number }>({
  destinationIdentity: participantIdentity,
  method: 'getUserLocation',
  payload: { highAccuracy: true },
}));