const getIncomingHeaders = createIsomorphicFn()
    .client(() => ({}))
    .server(() => getHeaders());

// ...

const trpcClient = createTRPCClient<TRPCRouter>({
    links: [
        httpBatchStreamLink({
            headers: getIncomingHeaders(),
            transformer: superjson,
            url: getUrl(),
        }),
    ],
});

const getIncomingHeaders = createIsomorphicFn()
    .client(() => ({}))
    .server(() => getHeaders());

// ...

const trpcClient = createTRPCClient<TRPCRouter>({
    links: [
        httpBatchStreamLink({
            headers: getIncomingHeaders(),
            transformer: superjson,
            url: getUrl(),
        }),
    ],
});